azam akhbari - Academia.edu (original) (raw)

Papers by azam akhbari

Research paper thumbnail of Photoinduced pyrene degradation in contaminated soils by polyaniline coated photocatalysts

F Shahrezaei, A Hemati Azandaryani, A M Mansourie, A Akhbari & P Pakravan * aAcademic Center for ... more F Shahrezaei, A Hemati Azandaryani, A M Mansourie, A Akhbari & P Pakravan * aAcademic Center for Education, Culture & Research (ACECR), Kermanshah, Iran bNano Drug Delivery Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran cResearch Center for Environmental Determination of Health (RCEDH), Kermanshah University of Medical Sciences, Kermanshah, Iran dDepartment of Civil Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur, Malaysia eDepartment of Chemistry, Zanjan Branch, Islamic Azad University, Zanjan, Iran

Research paper thumbnail of Optimization of up-flow velocity and feed flow rate in up-flow anaerobic sludge blanket fixed-film reactor on bio-hydrogen production from palm oil mill effluent

Research paper thumbnail of Bioenergy recovery from food waste through dark fermentation direction

The increase in food waste generation has encouraged the scientific community to convert it into ... more The increase in food waste generation has encouraged the scientific community to convert it into value-added resources. Hydrogen energy provides a sustainable option to fossil fuels due to its purity, high energy content, and reduction of global warming. This study investigates the batch fermentative biohydrogen production from food waste, which takes into account the effects on the process stability and energy recovery. Experiments were carried out at different ranges of pH (5.5, 6.0, and 6.5), FW concentration (1, 5, 10, 15, 20, 25, and 30 g-VS/L) at mesophilic (37˚C) and thermophilic (55˚C) temperature through 24h incubation of batch dark fermentation process. The FW concentration of 15–20 g-VS.L− 1 was found to be the proper concentration for biohydrogen production at 55˚C fermentation with the highest yield of 80.41 ml-H2/g-VS.L− 1, hydrogen content of 76.53%, at pH 6.0. Under mesophilic temperature, a lower hydrogen yield of 49.36 ml-H2/g-VS.L− 1and hydrogen content of 60.53% ...

Research paper thumbnail of Realizing higher value output from biomass conversion to biogas through the production of biohydrogen, biomethane, and biohythane

Value-Chain of Biofuels, 2022

Research paper thumbnail of Analysis of biohydrogen production from palm oil mill effluent using a pilot-scale up-flow anaerobic sludge blanket fixed-film reactor in life cycle perspective

International Journal of Hydrogen Energy, 2021

Abstract This study aims to analyse the life-cycle assessment of biohydrogen production from palm... more Abstract This study aims to analyse the life-cycle assessment of biohydrogen production from palm oil mill effluent (POME) in a pilot-scale up-flow anaerobic sludge blanket fixed-film reactor. The SimaPro LCA software and ReCiPe 2016 impact assessment method were used. Electricity usage was found to be a significant source of environmental impacts, with 50–98% of the total impacts. Furthermore, an improvement analysis was conducted, resulted in a reduction in all impacts, especially global warming impact with 77% reduction from 818 to 189 kg CO2-eq per kg biohydrogen. While shifting the pilot reactor to Sarawak may further lessen the impact to 142 kg CO2-eq due to cleaner grid in that region. Besides, if the environmental burden avoided due to usage of POME is considered, the global warming impact can be further reduced to 54.9 kg CO2-eq. Thus, the pilot reactor has huge potential, especially in utilizing waste to produce bioenergy.

Research paper thumbnail of Start‐Up Study on Biohydrogen from Palm Oil Mill Effluent in a Pilot‐Scale Reactor

CLEAN – Soil, Air, Water, 2020

Research paper thumbnail of Start-up study of biohydrogen production from palm oil mill effluent in a lab-scale up-flow anaerobic sludge blanket fixed-film reactor

International Journal of Hydrogen Energy, 2021

Abstract A start-up study of lab-scale up-flow anaerobic sludge blanket fixed-film reactor (UASFF... more Abstract A start-up study of lab-scale up-flow anaerobic sludge blanket fixed-film reactor (UASFF) was conducted to produce biohydrogen from palm oil mill effluent (POME). The reactor was fed with POME at different hydraulic retention time (HRT) and organic loading rate (OLR) to obtain the optimum fermentation time for maximum hydrogen yield (HY). The results showed the HY, volumetric hydrogen production rate (VHPR), and COD removal of 0.5–1.1 L H2/g CODconsumed, 1.98–4.1 L H2 L−1 day−1, and 33.4–38.5%, respectively. The characteristic study on POME particles was analyzed by particle size distribution (PSD), Scanning electron microscopy (SEM), and Energy-dispersive X-ray spectroscopy (EDX). The microbial Shannon and Simpson diversity indices and Principal Component Analysis assessed the alpha and beta diversity, respectively. The results indicated the change of bacterial community diversity over the operation, in which Clostridium sensu stricto 1 and Lactobacillus species were contributed to hydrogen fermentation.

Research paper thumbnail of Performance assessment of modified clinoptilolite and magnetic nanotubes on sulfate removal and potential application in natural river samples

Journal of Inclusion Phenomena and Macrocyclic Chemistry, 2020

This study presents the adsorption of sulfate by clinoptilolite and magnetic nanotubes (MNT) from... more This study presents the adsorption of sulfate by clinoptilolite and magnetic nanotubes (MNT) from the Gamasiab river (Kermanshah, Iran) samples. The samples have been characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier-transform infrared spectroscopy (FT-IR). The results showed that selective methods were implemented properly for nanoparticle preparation. During the process operating, time was considered as the most significant factor in sulfate removal. Moreover, adsorbent to pollutant ratios (D/C), and pH was selected as control variables. The design of the experiment was used to find the optimal conditions for the use of adsorbents. The optimum adsorption points were obtained for the MNT at pH 8.97 and D/C = 6.12 and the clinoptilolite at pH 10.68 and D/C = 22.07. The effect of pH on the adsorbents indicated that the adsorbent performance in the alkaline condition has the highest efficiency. Hence, for MNTs, increasing pH value increased the adsorbance amount. To investigate the effect of D/C, the rate of adsorption showed an ascending trend. In addition, the equilibrium data were defined by Langmuir and Freundlich isotherm models, respectively. Freundlich isotherm well described the process of adsorbing sulfate by clinoptilolite with a correlation coefficient of 0.918. While the Langmuir isotherm was consistent with the adsorption process of sulfate by MNT with a correlation coefficient of 0.9728. The efficiency of sulfate adsorption for clinoptilolite and MNT in the natural river samples was calculated 91.5% and 97.8%, respectively. The results showed the superiority of MNT adsorption capability in river water conditions.

Research paper thumbnail of UASFF start-up for biohydrogen and biomethane production from treatment of Palm Oil Mill Effluent

International Journal of Hydrogen Energy, 2019

A start-up study was conducted to produce biohydrogen and biomethane from Palm Oil Mill Effluent ... more A start-up study was conducted to produce biohydrogen and biomethane from Palm Oil Mill Effluent (POME) using a two-stage up-flow anaerobic sludge fixed-film (UASFF) bioreactor. 100% molasses was used to start the system, and POME was added at 10% increments until it reached 100% after 59 days. During this period of continuous operation, the HRT and temperature were adjusted in order to optimize the condition for biogas production. Hydrogen and methane gas production fluctuated between 53e70% and 90e95%, respectively, in the last four days of operation (days 56e59), with POME percentage being increased from 70% to 100% (30%e0% molasses). Using 100% raw POME led to a total COD removal of 83.70%, average gas production rates of 5.29 L H 2 d À1 (57.11% H 2) and 9.60 L CH 4 d À1 (94.08% CH 4), in their respective units. This output is comparable to, if not better than using 100% molasses as substrate. This work concludes that based on the relative consistency of biogas production on days 56e59, the two-stage UASFF bioreactor operating at a final HRT of 4 h and temperature of 43 C has taken a period of two months for start-up.

Research paper thumbnail of Biodiesel production from sunflower oil using electrochemical reaction as a green, low-cost and room temperature method: modeling and optimization by RSM

DESALINATION AND WATER TREATMENT, 2017

Nowadays, conversion of waste feedstocks to biodiesel production as a renewable energy source is ... more Nowadays, conversion of waste feedstocks to biodiesel production as a renewable energy source is in a high demand. Biodiesel can be attained from oils and fats by transesterification process. Traditionally, biodiesel achieves from vegetable oils and raw materials as feedstock which should be free of water. The disadvantages of the process with the presence of water are catalyst consumption, effectiveness reduction, and soap formation. In this project, a catalyst-free method was used for biodiesel fuel production by using the electrochemical method with graphite electrodes in the presence of high values of water. Response surface methodology along with central composite design was used to optimize the reaction conditions. The impact of main factors, i.e. voltage (5-35V), CH 3 OH/oil molar ratio (6-18), water content (2-10%), and reaction time (1-3 h), the effect on the biodiesel production are discussed. The maximum biodiesel production yield (81%) was obtained at the optimum conditions: the voltage of 35 V, CH 3 OH/oil molar ratio of 18, the water content of 2%, and the reaction time of 3 h. Therefore, this study investigates the electrochemical method as a reliable approach in the biodiesel production analysis due to less sensitivity to the water.

Research paper thumbnail of A study of palm oil mill processing and environmental assessment of palm oil mill effluent treatment

Environmental Engineering Research, 2019

This work discusses the palm oil mill processing carried out at Jugra Palm Oil Mill Sdn Bhd, situ... more This work discusses the palm oil mill processing carried out at Jugra Palm Oil Mill Sdn Bhd, situated at Selangor, Malaysia with the capacity of 45-t fresh fruit bunch (FFB)/h. Typically, oil palm residues and palm oil mill effluent (POME) from FFB are generated while processing. Prior to discharge, POME should be treated to remove pollutants in the effluent. As such, the performances of anaerobic and aerobic ponds were assessed in this study to determine temperature, pH, biological oxygen demand (BOD), sludge volume index (SVI), and dissolved oxygen (DO). From the experiments, mesophilic temperature due to better process stability was applied in anaerobic ponds. The pH results displayed a fluctuating trend between lower control limit and upper control limit, and, the pH value increased from one pond to another. The final discharge BOD and SVI appeared to be lower than 100 mg/L and 10 mL/L indicating low degree of pollution and good settling ability for biomass/solid. DO was close to normal, mostly below 2 mg/L. The experimental outcomes revealed the effective treatability of POME in adherence to the standard regulation, which is the priority for environmental sustainability within this industry domain.

Research paper thumbnail of Effect of operational variables on biological hydrogen production from palm oil mill effluent by dark fermentation using response surface methodology

DESALINATION AND WATER TREATMENT, 2019

This work is a study of the performance and effect of operational parameters on biohydrogen produ... more This work is a study of the performance and effect of operational parameters on biohydrogen production from palm oil mill effluent by dark fermentation in batch mode. The tests were conducted with samples prepared in 150 mL bottles using a shaker at 150 rpm. Response surface methodology was applied to investigate the influence of the four significant independent parameters viz. pH (5, 5.5, and 6), temperature (30°C, 35°C, and 40°C), substrate concentration (5,000, 12,500, and 20,000 mg L-1) and inoculum-substrate ratios of 2, 0.8, and 0.5 (expressed as volatile suspended solid (VSS) basis) with the inoculum concentration of 10 g L-1 VSS on biohydrogen production. All the experiments were analyzed at the incubation time of 8, 16, and 24 h. Upon seeing each interval, the results were compared. The highest chemical oxygen demand (COD) removal, the hydrogen content in the biogas as hydrogen percentage (H 2 %), and hydrogen yield (HY) were obtained 58.3%, 80%, and 3.63 mol H 2 mol-1 glucose, respectively, at 24 h incubation time. An overlay study was done to find an overall optimization of the parameters. The optimized conditions were COD removal 49%, HY 3.2 mol H 2 mol-1 glucose, and hydrogen percentage 80%. Also, the Monod model was studied to calculate the kinetics constants of the maximum substrate utilization rate (U max) and half-velocity K s which are found to be 0.261 g L-1 d-1 and 0.349 mg L-1 , respectively.

Research paper thumbnail of Evolutionary Prediction of Biohydrogen Production by Dark Fermentation

CLEAN - Soil, Air, Water, 2018

The present work is a study of the performance and effect of operational parameters on biohydroge... more The present work is a study of the performance and effect of operational parameters on biohydrogen production from palm oil mill effluent by dark fermentation in batch mode. The process parameters examined are pH (5, 5.5 and 6), temperature (30, 35, and 40°C), substrate concentration (5000, 12 500 and 20 000 mg L-1) and inoculum volume (20, 25 and 30 mL). The inoculum concentration prepared was 10000 mg L-1 volatile suspended solids. The experiments were designed by response surface methodology (RSM). The highest chemical oxygen demand (COD) removal, hydrogen percentage (H 2 %) and hydrogen yield (HY) obtained were 58.3%, 80% and 4.83 mol H 2 /mole of COD consumed, respectively. Based on the experimental data obtained with the RSM design, gene expression programming (GEP) was developed to predict the COD removal, hydrogen production and hydrogen yield as process responses. The projected models were assessed based on the correlation coefficient (R 2), root mean square error, mean absolute relative error, scatter index and BIAS. The results demonstrate that the GEP model outperformed the RSM model and was superior in predicting the response variables. Partial derivative sensitivity analysis was also employed to assess the effect of each variable on COD%, H 2 %, and HY prediction. The prediction uncertainty for COD%, H 2 %, and HY was quantified, and the results were ±0.11, ±0.17 and 0.015, respectively. According to the results, the GEP model was more efficient than the RSM model in predicting the experimental data for biological hydrogen production in the dark fermentation process.

Research paper thumbnail of Calculating the energy consumption of electrocoagulation using a generalized structure group method of data handling integrated with a genetic algorithm and singular value decomposition

Clean Technologies and Environmental Policy, 2018

Research paper thumbnail of Kinetic Evaluation of Simultaneous CNP Removal in an up-Flow Aerobic/Anoxic Sludge Fixed Film (UAASFF) Bioreactor

Iranica Journal of energy and environment, 2014

The kinetics of simultaneous removal of carbon, nitrogen and phosphorus from a synthetic wastewat... more The kinetics of simultaneous removal of carbon, nitrogen and phosphorus from a synthetic wastewater in an innovative up-flow aerobic/anoxic sludge fixed film (UAASFF) bioreactor was investigated. The kinetic analysis was performed using the experimental data obtained in an earlier study where the UAASFF bioreactor was examined under different operating conditions by changing three independent variables, HRT, COD:N:P ratio and aeration time. In the analysis, different kinetic models (Monod, first-order, second-order and Stover-Kincannon models) were evaluated. The maximum removal efficiency of COD, total nitrogen (TN) and phosphorus (TP) were obtained to be 95.42, 79 and 79.1 %, respectively. All the models examined, gave high correlation coefficients for carbon, nitrogen and phosphorus removal. Biokinetic coefficients were determined as Y= 0.417-0.496 g VSS/g COD, k = 0.027-0.053 d , µ =1.36 g VSS /g VSS.d, K =37.96 g/l.d U =38.46 g/l.d,

Research paper thumbnail of Multi-objective evolutionary polynomial regression-based prediction of energy consumption probing

Water Science and Technology, 2017

Electrocoagulation (EC) is employed to investigate the energy consumption (EnC) of synthetic wast... more Electrocoagulation (EC) is employed to investigate the energy consumption (EnC) of synthetic wastewater. In order to find the best process conditions, the influence of various parameters including initial pH, initial dye concentration, applied voltage, initial electrolyte concentration, and treatment time are investigated in this study. EnC is considered the main criterion of process evaluation in investigating the effect of the independent variables on the EC process and determining the optimum condition. Evolutionary polynomial regression is combined with a multi-objective genetic algorithm (EPR-MOGA) to present a new, simple and accurate equation for estimating EnC to overcome existing method weaknesses. To survey the influence of the effective variables, six different input combinations are considered. According to the results, EPR-MOGA Model 1 is the most accurate compared to other models, as it has the lowest error indices in predicting EnC (MARE = 0.35, RMSE = 2.33, SI = 0.23...

Research paper thumbnail of Evolutionary prediction of electrocoagulation efficiency and energy consumption probing

DESALINATION AND WATER TREATMENT, 2017

This case study focuses on the color removal efficiency (CR%) and energy consumption (EnC) of ele... more This case study focuses on the color removal efficiency (CR%) and energy consumption (EnC) of electrocoagulation (EC) using synthetic wastewater containing disperses like orange 25 dye. Process parameters including initial pH (pH 0), initial dye concentration (C 0), applied voltage (V EC), initial electrolyte concentration (C S) and treatment time (t EC) were found to be the more effective EC operational parameters to attain maximum decolorization efficiency. In order to investigate the effect of the independent variables on dye removal and determine the optimum condition, gene expression programming (GEP) was used, and the results were compared with the reduced quadratic multiple regression model (SMLR) method. The results indicate that the proposed model predicted the CR% with MARE of 17.28 and RMSE of 6.24, and EnC with MARE of 54.876 and RMSE of 5.33. This model can make more accurate predictions than the SMLR equations. The GEP technique presents two simple equations for predicting CR% and EnC for practical engineering. Also, two different explicit expressions are presented to estimate CR% and EnC as an alternative tool in practical. Moreover, a partial derivative sensitivity analysis was used to indicate the trend of each parameter in the proposed models.

Research paper thumbnail of Predicting discharge coefficient of triangular labyrinth weir using extreme learning machine, artificial neural network and genetic programming

Neural Computing and Applications, 2016

Weirs are installed on open channels to adjust and measure the flow. Also, discharge coefficient ... more Weirs are installed on open channels to adjust and measure the flow. Also, discharge coefficient is considered as the most important hydraulic parameter of a weir. In this study, using the Radial Base Neural Networks (RBNN) and M5' methods, the discharge coefficient of triangular plan form weirs is modeled. At first, the effective parameters in the prediction of the discharge coefficient are identified. Then, by combining the input parameters, for each of the RBNN and M5' methods, six different models are introduced. By analyzing the modeling results for all models, it was shown that the M5' model is capable of modeling the discharge coefficient more accurately. Also, based on the modeling results, a model that considered the impact of all input parameters was introduced as a superior model. The mean absolute percentage error (MAPE) and correlation coefficients (R 2) values for the preferred model in the test mode were calculated 2.774 and 0.831, respectively. Also, for each of the M5' models, some relationships were proposed to estimate the triangular plan form weirs. The evaluation of these relationships showed that the parameters of the ratio of head over the weir to channel width (h/B) and Froude number (Fr) were the most effective parameters in the prediction of the discharge coefficient.

Research paper thumbnail of Biological treatment of a synthetic dairy wastewater in a sequencing batch biofilm reactor: Statistical modeling using optimization using response surface methodology

Chemical Industry and Chemical Engineering Quarterly, 2011

In this study, the interactive effects of initial chemical oxygen demand (CODin), biomass concent... more In this study, the interactive effects of initial chemical oxygen demand (CODin), biomass concentration and aeration time on the performance of a lab-scale sequencing batch biofilm reactor (SBBR) treating a synthetic dairy wastewater were investigated. The experiments were conducted based on a central composite design (CCD) and analyzed using response surface methodology (RSM). The region of exploration for treatment of the synthetic dairy wastewater was taken as the area enclosed by the influent comical oxygen demand (CODin (1000, 3000 and 5000 mg/l)), biomass concentration (3000, 5000 and 7000 mg VSS/l) and aeration time (2, 8 and 18 h) boundaries. Two dependent parameters were measured or calculated as response. These parameters were total COD removal efficiency and sludge volume index (SVI). The maximum COD removal efficiencies (99.5%) were obtained at CODin, biomass concentration and aeration time of 5000 mg COD/l, 7000 mg VSS/l and 18 h, respectively. The present study provide...

Research paper thumbnail of Photocatalytic Degradation of Aniline Using TiO2Nanoparticles in a Vertical Circulating Photocatalytic Reactor

International Journal of Photoenergy, 2012

Photocatalytic degradation of aniline in the presence of titanium dioxide (TiO2) and ultraviolet ... more Photocatalytic degradation of aniline in the presence of titanium dioxide (TiO2) and ultraviolet (UV) illumination was performed in a vertical circulating photocatalytic reactor. The effects of catalyst concentration (0–80 mg/L), initial pH (2–12), temperature (293–323 K), and irradiation time (0–120 min) on aniline photodegradation were investigated in order to obtain the optimum operational conditions. The results reveal that the aniline degradation efficiency can be effectively improved by increasing pH from 2 to 12 and temperature from 313 to 323 K. Besides, the effect of temperature on aniline photo degradation was found to be unremarkable in the range of 293–313 K. The optimum catalyst concentration was about 60 mg/L. The Langmuir Hinshelwood kinetic model could successfully elucidate the effects of the catalyst concentration, pH, and temperature on the rate of heterogeneous photooxidation of aniline. The data obtained by applying the Langmuir Hinshelwood treatment are consist...

Research paper thumbnail of Photoinduced pyrene degradation in contaminated soils by polyaniline coated photocatalysts

F Shahrezaei, A Hemati Azandaryani, A M Mansourie, A Akhbari & P Pakravan * aAcademic Center for ... more F Shahrezaei, A Hemati Azandaryani, A M Mansourie, A Akhbari & P Pakravan * aAcademic Center for Education, Culture & Research (ACECR), Kermanshah, Iran bNano Drug Delivery Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran cResearch Center for Environmental Determination of Health (RCEDH), Kermanshah University of Medical Sciences, Kermanshah, Iran dDepartment of Civil Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur, Malaysia eDepartment of Chemistry, Zanjan Branch, Islamic Azad University, Zanjan, Iran

Research paper thumbnail of Optimization of up-flow velocity and feed flow rate in up-flow anaerobic sludge blanket fixed-film reactor on bio-hydrogen production from palm oil mill effluent

Research paper thumbnail of Bioenergy recovery from food waste through dark fermentation direction

The increase in food waste generation has encouraged the scientific community to convert it into ... more The increase in food waste generation has encouraged the scientific community to convert it into value-added resources. Hydrogen energy provides a sustainable option to fossil fuels due to its purity, high energy content, and reduction of global warming. This study investigates the batch fermentative biohydrogen production from food waste, which takes into account the effects on the process stability and energy recovery. Experiments were carried out at different ranges of pH (5.5, 6.0, and 6.5), FW concentration (1, 5, 10, 15, 20, 25, and 30 g-VS/L) at mesophilic (37˚C) and thermophilic (55˚C) temperature through 24h incubation of batch dark fermentation process. The FW concentration of 15–20 g-VS.L− 1 was found to be the proper concentration for biohydrogen production at 55˚C fermentation with the highest yield of 80.41 ml-H2/g-VS.L− 1, hydrogen content of 76.53%, at pH 6.0. Under mesophilic temperature, a lower hydrogen yield of 49.36 ml-H2/g-VS.L− 1and hydrogen content of 60.53% ...

Research paper thumbnail of Realizing higher value output from biomass conversion to biogas through the production of biohydrogen, biomethane, and biohythane

Value-Chain of Biofuels, 2022

Research paper thumbnail of Analysis of biohydrogen production from palm oil mill effluent using a pilot-scale up-flow anaerobic sludge blanket fixed-film reactor in life cycle perspective

International Journal of Hydrogen Energy, 2021

Abstract This study aims to analyse the life-cycle assessment of biohydrogen production from palm... more Abstract This study aims to analyse the life-cycle assessment of biohydrogen production from palm oil mill effluent (POME) in a pilot-scale up-flow anaerobic sludge blanket fixed-film reactor. The SimaPro LCA software and ReCiPe 2016 impact assessment method were used. Electricity usage was found to be a significant source of environmental impacts, with 50–98% of the total impacts. Furthermore, an improvement analysis was conducted, resulted in a reduction in all impacts, especially global warming impact with 77% reduction from 818 to 189 kg CO2-eq per kg biohydrogen. While shifting the pilot reactor to Sarawak may further lessen the impact to 142 kg CO2-eq due to cleaner grid in that region. Besides, if the environmental burden avoided due to usage of POME is considered, the global warming impact can be further reduced to 54.9 kg CO2-eq. Thus, the pilot reactor has huge potential, especially in utilizing waste to produce bioenergy.

Research paper thumbnail of Start‐Up Study on Biohydrogen from Palm Oil Mill Effluent in a Pilot‐Scale Reactor

CLEAN – Soil, Air, Water, 2020

Research paper thumbnail of Start-up study of biohydrogen production from palm oil mill effluent in a lab-scale up-flow anaerobic sludge blanket fixed-film reactor

International Journal of Hydrogen Energy, 2021

Abstract A start-up study of lab-scale up-flow anaerobic sludge blanket fixed-film reactor (UASFF... more Abstract A start-up study of lab-scale up-flow anaerobic sludge blanket fixed-film reactor (UASFF) was conducted to produce biohydrogen from palm oil mill effluent (POME). The reactor was fed with POME at different hydraulic retention time (HRT) and organic loading rate (OLR) to obtain the optimum fermentation time for maximum hydrogen yield (HY). The results showed the HY, volumetric hydrogen production rate (VHPR), and COD removal of 0.5–1.1 L H2/g CODconsumed, 1.98–4.1 L H2 L−1 day−1, and 33.4–38.5%, respectively. The characteristic study on POME particles was analyzed by particle size distribution (PSD), Scanning electron microscopy (SEM), and Energy-dispersive X-ray spectroscopy (EDX). The microbial Shannon and Simpson diversity indices and Principal Component Analysis assessed the alpha and beta diversity, respectively. The results indicated the change of bacterial community diversity over the operation, in which Clostridium sensu stricto 1 and Lactobacillus species were contributed to hydrogen fermentation.

Research paper thumbnail of Performance assessment of modified clinoptilolite and magnetic nanotubes on sulfate removal and potential application in natural river samples

Journal of Inclusion Phenomena and Macrocyclic Chemistry, 2020

This study presents the adsorption of sulfate by clinoptilolite and magnetic nanotubes (MNT) from... more This study presents the adsorption of sulfate by clinoptilolite and magnetic nanotubes (MNT) from the Gamasiab river (Kermanshah, Iran) samples. The samples have been characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier-transform infrared spectroscopy (FT-IR). The results showed that selective methods were implemented properly for nanoparticle preparation. During the process operating, time was considered as the most significant factor in sulfate removal. Moreover, adsorbent to pollutant ratios (D/C), and pH was selected as control variables. The design of the experiment was used to find the optimal conditions for the use of adsorbents. The optimum adsorption points were obtained for the MNT at pH 8.97 and D/C = 6.12 and the clinoptilolite at pH 10.68 and D/C = 22.07. The effect of pH on the adsorbents indicated that the adsorbent performance in the alkaline condition has the highest efficiency. Hence, for MNTs, increasing pH value increased the adsorbance amount. To investigate the effect of D/C, the rate of adsorption showed an ascending trend. In addition, the equilibrium data were defined by Langmuir and Freundlich isotherm models, respectively. Freundlich isotherm well described the process of adsorbing sulfate by clinoptilolite with a correlation coefficient of 0.918. While the Langmuir isotherm was consistent with the adsorption process of sulfate by MNT with a correlation coefficient of 0.9728. The efficiency of sulfate adsorption for clinoptilolite and MNT in the natural river samples was calculated 91.5% and 97.8%, respectively. The results showed the superiority of MNT adsorption capability in river water conditions.

Research paper thumbnail of UASFF start-up for biohydrogen and biomethane production from treatment of Palm Oil Mill Effluent

International Journal of Hydrogen Energy, 2019

A start-up study was conducted to produce biohydrogen and biomethane from Palm Oil Mill Effluent ... more A start-up study was conducted to produce biohydrogen and biomethane from Palm Oil Mill Effluent (POME) using a two-stage up-flow anaerobic sludge fixed-film (UASFF) bioreactor. 100% molasses was used to start the system, and POME was added at 10% increments until it reached 100% after 59 days. During this period of continuous operation, the HRT and temperature were adjusted in order to optimize the condition for biogas production. Hydrogen and methane gas production fluctuated between 53e70% and 90e95%, respectively, in the last four days of operation (days 56e59), with POME percentage being increased from 70% to 100% (30%e0% molasses). Using 100% raw POME led to a total COD removal of 83.70%, average gas production rates of 5.29 L H 2 d À1 (57.11% H 2) and 9.60 L CH 4 d À1 (94.08% CH 4), in their respective units. This output is comparable to, if not better than using 100% molasses as substrate. This work concludes that based on the relative consistency of biogas production on days 56e59, the two-stage UASFF bioreactor operating at a final HRT of 4 h and temperature of 43 C has taken a period of two months for start-up.

Research paper thumbnail of Biodiesel production from sunflower oil using electrochemical reaction as a green, low-cost and room temperature method: modeling and optimization by RSM

DESALINATION AND WATER TREATMENT, 2017

Nowadays, conversion of waste feedstocks to biodiesel production as a renewable energy source is ... more Nowadays, conversion of waste feedstocks to biodiesel production as a renewable energy source is in a high demand. Biodiesel can be attained from oils and fats by transesterification process. Traditionally, biodiesel achieves from vegetable oils and raw materials as feedstock which should be free of water. The disadvantages of the process with the presence of water are catalyst consumption, effectiveness reduction, and soap formation. In this project, a catalyst-free method was used for biodiesel fuel production by using the electrochemical method with graphite electrodes in the presence of high values of water. Response surface methodology along with central composite design was used to optimize the reaction conditions. The impact of main factors, i.e. voltage (5-35V), CH 3 OH/oil molar ratio (6-18), water content (2-10%), and reaction time (1-3 h), the effect on the biodiesel production are discussed. The maximum biodiesel production yield (81%) was obtained at the optimum conditions: the voltage of 35 V, CH 3 OH/oil molar ratio of 18, the water content of 2%, and the reaction time of 3 h. Therefore, this study investigates the electrochemical method as a reliable approach in the biodiesel production analysis due to less sensitivity to the water.

Research paper thumbnail of A study of palm oil mill processing and environmental assessment of palm oil mill effluent treatment

Environmental Engineering Research, 2019

This work discusses the palm oil mill processing carried out at Jugra Palm Oil Mill Sdn Bhd, situ... more This work discusses the palm oil mill processing carried out at Jugra Palm Oil Mill Sdn Bhd, situated at Selangor, Malaysia with the capacity of 45-t fresh fruit bunch (FFB)/h. Typically, oil palm residues and palm oil mill effluent (POME) from FFB are generated while processing. Prior to discharge, POME should be treated to remove pollutants in the effluent. As such, the performances of anaerobic and aerobic ponds were assessed in this study to determine temperature, pH, biological oxygen demand (BOD), sludge volume index (SVI), and dissolved oxygen (DO). From the experiments, mesophilic temperature due to better process stability was applied in anaerobic ponds. The pH results displayed a fluctuating trend between lower control limit and upper control limit, and, the pH value increased from one pond to another. The final discharge BOD and SVI appeared to be lower than 100 mg/L and 10 mL/L indicating low degree of pollution and good settling ability for biomass/solid. DO was close to normal, mostly below 2 mg/L. The experimental outcomes revealed the effective treatability of POME in adherence to the standard regulation, which is the priority for environmental sustainability within this industry domain.

Research paper thumbnail of Effect of operational variables on biological hydrogen production from palm oil mill effluent by dark fermentation using response surface methodology

DESALINATION AND WATER TREATMENT, 2019

This work is a study of the performance and effect of operational parameters on biohydrogen produ... more This work is a study of the performance and effect of operational parameters on biohydrogen production from palm oil mill effluent by dark fermentation in batch mode. The tests were conducted with samples prepared in 150 mL bottles using a shaker at 150 rpm. Response surface methodology was applied to investigate the influence of the four significant independent parameters viz. pH (5, 5.5, and 6), temperature (30°C, 35°C, and 40°C), substrate concentration (5,000, 12,500, and 20,000 mg L-1) and inoculum-substrate ratios of 2, 0.8, and 0.5 (expressed as volatile suspended solid (VSS) basis) with the inoculum concentration of 10 g L-1 VSS on biohydrogen production. All the experiments were analyzed at the incubation time of 8, 16, and 24 h. Upon seeing each interval, the results were compared. The highest chemical oxygen demand (COD) removal, the hydrogen content in the biogas as hydrogen percentage (H 2 %), and hydrogen yield (HY) were obtained 58.3%, 80%, and 3.63 mol H 2 mol-1 glucose, respectively, at 24 h incubation time. An overlay study was done to find an overall optimization of the parameters. The optimized conditions were COD removal 49%, HY 3.2 mol H 2 mol-1 glucose, and hydrogen percentage 80%. Also, the Monod model was studied to calculate the kinetics constants of the maximum substrate utilization rate (U max) and half-velocity K s which are found to be 0.261 g L-1 d-1 and 0.349 mg L-1 , respectively.

Research paper thumbnail of Evolutionary Prediction of Biohydrogen Production by Dark Fermentation

CLEAN - Soil, Air, Water, 2018

The present work is a study of the performance and effect of operational parameters on biohydroge... more The present work is a study of the performance and effect of operational parameters on biohydrogen production from palm oil mill effluent by dark fermentation in batch mode. The process parameters examined are pH (5, 5.5 and 6), temperature (30, 35, and 40°C), substrate concentration (5000, 12 500 and 20 000 mg L-1) and inoculum volume (20, 25 and 30 mL). The inoculum concentration prepared was 10000 mg L-1 volatile suspended solids. The experiments were designed by response surface methodology (RSM). The highest chemical oxygen demand (COD) removal, hydrogen percentage (H 2 %) and hydrogen yield (HY) obtained were 58.3%, 80% and 4.83 mol H 2 /mole of COD consumed, respectively. Based on the experimental data obtained with the RSM design, gene expression programming (GEP) was developed to predict the COD removal, hydrogen production and hydrogen yield as process responses. The projected models were assessed based on the correlation coefficient (R 2), root mean square error, mean absolute relative error, scatter index and BIAS. The results demonstrate that the GEP model outperformed the RSM model and was superior in predicting the response variables. Partial derivative sensitivity analysis was also employed to assess the effect of each variable on COD%, H 2 %, and HY prediction. The prediction uncertainty for COD%, H 2 %, and HY was quantified, and the results were ±0.11, ±0.17 and 0.015, respectively. According to the results, the GEP model was more efficient than the RSM model in predicting the experimental data for biological hydrogen production in the dark fermentation process.

Research paper thumbnail of Calculating the energy consumption of electrocoagulation using a generalized structure group method of data handling integrated with a genetic algorithm and singular value decomposition

Clean Technologies and Environmental Policy, 2018

Research paper thumbnail of Kinetic Evaluation of Simultaneous CNP Removal in an up-Flow Aerobic/Anoxic Sludge Fixed Film (UAASFF) Bioreactor

Iranica Journal of energy and environment, 2014

The kinetics of simultaneous removal of carbon, nitrogen and phosphorus from a synthetic wastewat... more The kinetics of simultaneous removal of carbon, nitrogen and phosphorus from a synthetic wastewater in an innovative up-flow aerobic/anoxic sludge fixed film (UAASFF) bioreactor was investigated. The kinetic analysis was performed using the experimental data obtained in an earlier study where the UAASFF bioreactor was examined under different operating conditions by changing three independent variables, HRT, COD:N:P ratio and aeration time. In the analysis, different kinetic models (Monod, first-order, second-order and Stover-Kincannon models) were evaluated. The maximum removal efficiency of COD, total nitrogen (TN) and phosphorus (TP) were obtained to be 95.42, 79 and 79.1 %, respectively. All the models examined, gave high correlation coefficients for carbon, nitrogen and phosphorus removal. Biokinetic coefficients were determined as Y= 0.417-0.496 g VSS/g COD, k = 0.027-0.053 d , µ =1.36 g VSS /g VSS.d, K =37.96 g/l.d U =38.46 g/l.d,

Research paper thumbnail of Multi-objective evolutionary polynomial regression-based prediction of energy consumption probing

Water Science and Technology, 2017

Electrocoagulation (EC) is employed to investigate the energy consumption (EnC) of synthetic wast... more Electrocoagulation (EC) is employed to investigate the energy consumption (EnC) of synthetic wastewater. In order to find the best process conditions, the influence of various parameters including initial pH, initial dye concentration, applied voltage, initial electrolyte concentration, and treatment time are investigated in this study. EnC is considered the main criterion of process evaluation in investigating the effect of the independent variables on the EC process and determining the optimum condition. Evolutionary polynomial regression is combined with a multi-objective genetic algorithm (EPR-MOGA) to present a new, simple and accurate equation for estimating EnC to overcome existing method weaknesses. To survey the influence of the effective variables, six different input combinations are considered. According to the results, EPR-MOGA Model 1 is the most accurate compared to other models, as it has the lowest error indices in predicting EnC (MARE = 0.35, RMSE = 2.33, SI = 0.23...

Research paper thumbnail of Evolutionary prediction of electrocoagulation efficiency and energy consumption probing

DESALINATION AND WATER TREATMENT, 2017

This case study focuses on the color removal efficiency (CR%) and energy consumption (EnC) of ele... more This case study focuses on the color removal efficiency (CR%) and energy consumption (EnC) of electrocoagulation (EC) using synthetic wastewater containing disperses like orange 25 dye. Process parameters including initial pH (pH 0), initial dye concentration (C 0), applied voltage (V EC), initial electrolyte concentration (C S) and treatment time (t EC) were found to be the more effective EC operational parameters to attain maximum decolorization efficiency. In order to investigate the effect of the independent variables on dye removal and determine the optimum condition, gene expression programming (GEP) was used, and the results were compared with the reduced quadratic multiple regression model (SMLR) method. The results indicate that the proposed model predicted the CR% with MARE of 17.28 and RMSE of 6.24, and EnC with MARE of 54.876 and RMSE of 5.33. This model can make more accurate predictions than the SMLR equations. The GEP technique presents two simple equations for predicting CR% and EnC for practical engineering. Also, two different explicit expressions are presented to estimate CR% and EnC as an alternative tool in practical. Moreover, a partial derivative sensitivity analysis was used to indicate the trend of each parameter in the proposed models.

Research paper thumbnail of Predicting discharge coefficient of triangular labyrinth weir using extreme learning machine, artificial neural network and genetic programming

Neural Computing and Applications, 2016

Weirs are installed on open channels to adjust and measure the flow. Also, discharge coefficient ... more Weirs are installed on open channels to adjust and measure the flow. Also, discharge coefficient is considered as the most important hydraulic parameter of a weir. In this study, using the Radial Base Neural Networks (RBNN) and M5' methods, the discharge coefficient of triangular plan form weirs is modeled. At first, the effective parameters in the prediction of the discharge coefficient are identified. Then, by combining the input parameters, for each of the RBNN and M5' methods, six different models are introduced. By analyzing the modeling results for all models, it was shown that the M5' model is capable of modeling the discharge coefficient more accurately. Also, based on the modeling results, a model that considered the impact of all input parameters was introduced as a superior model. The mean absolute percentage error (MAPE) and correlation coefficients (R 2) values for the preferred model in the test mode were calculated 2.774 and 0.831, respectively. Also, for each of the M5' models, some relationships were proposed to estimate the triangular plan form weirs. The evaluation of these relationships showed that the parameters of the ratio of head over the weir to channel width (h/B) and Froude number (Fr) were the most effective parameters in the prediction of the discharge coefficient.

Research paper thumbnail of Biological treatment of a synthetic dairy wastewater in a sequencing batch biofilm reactor: Statistical modeling using optimization using response surface methodology

Chemical Industry and Chemical Engineering Quarterly, 2011

In this study, the interactive effects of initial chemical oxygen demand (CODin), biomass concent... more In this study, the interactive effects of initial chemical oxygen demand (CODin), biomass concentration and aeration time on the performance of a lab-scale sequencing batch biofilm reactor (SBBR) treating a synthetic dairy wastewater were investigated. The experiments were conducted based on a central composite design (CCD) and analyzed using response surface methodology (RSM). The region of exploration for treatment of the synthetic dairy wastewater was taken as the area enclosed by the influent comical oxygen demand (CODin (1000, 3000 and 5000 mg/l)), biomass concentration (3000, 5000 and 7000 mg VSS/l) and aeration time (2, 8 and 18 h) boundaries. Two dependent parameters were measured or calculated as response. These parameters were total COD removal efficiency and sludge volume index (SVI). The maximum COD removal efficiencies (99.5%) were obtained at CODin, biomass concentration and aeration time of 5000 mg COD/l, 7000 mg VSS/l and 18 h, respectively. The present study provide...

Research paper thumbnail of Photocatalytic Degradation of Aniline Using TiO2Nanoparticles in a Vertical Circulating Photocatalytic Reactor

International Journal of Photoenergy, 2012

Photocatalytic degradation of aniline in the presence of titanium dioxide (TiO2) and ultraviolet ... more Photocatalytic degradation of aniline in the presence of titanium dioxide (TiO2) and ultraviolet (UV) illumination was performed in a vertical circulating photocatalytic reactor. The effects of catalyst concentration (0–80 mg/L), initial pH (2–12), temperature (293–323 K), and irradiation time (0–120 min) on aniline photodegradation were investigated in order to obtain the optimum operational conditions. The results reveal that the aniline degradation efficiency can be effectively improved by increasing pH from 2 to 12 and temperature from 313 to 323 K. Besides, the effect of temperature on aniline photo degradation was found to be unremarkable in the range of 293–313 K. The optimum catalyst concentration was about 60 mg/L. The Langmuir Hinshelwood kinetic model could successfully elucidate the effects of the catalyst concentration, pH, and temperature on the rate of heterogeneous photooxidation of aniline. The data obtained by applying the Langmuir Hinshelwood treatment are consist...