Sasirot Khamkure - Academia.edu (original) (raw)
Papers by Sasirot Khamkure
IntechOpen eBooks, May 13, 2024
Arsenic, a widespread contaminant, has become a major public health concern, threatening millions... more Arsenic, a widespread contaminant, has become a major public health concern, threatening millions globally. This study aims to develop magnetic adsorbents for easy recovery from aqueous media to remove arsenic, mitigating its environmental and health impacts. Response surface methodology (RSM) is proposed to optimize the adsorption-desorption process of As(III) and As(V) on carbon xerogel nanocomposites from aqueous solutions. A second-order polynomial model under a central composite design with a central face was employed to optimize arsenic desorption. The model parameters were estimated using least squares. Additionally, a novel linear model approach was employed to develop a second-degree polynomial model for optimizing arsenic adsorption-desorption by analyzing the effects of various factor combinations. RSM's ability to analyze the response variable over a wide range of independent variable values allows it to identify the region where the response variable reaches its optimum value.
Gels
Inorganic arsenic in drinking water from groundwater sources is one of the potential causes of ar... more Inorganic arsenic in drinking water from groundwater sources is one of the potential causes of arsenic-contaminated environments, and it is highly toxic to human health even at low concentrations. The purpose of this study was to develop a magnetic adsorbent capable of removing arsenic from water. Fe3O4-monolithic resorcinol-formaldehyde carbon xerogels are a type of porous material that forms when resorcinol and formaldehyde (RF) react to form a polymer network, which is then cross-linked with magnetite. Sonication-assisted direct and indirect methods were investigated for loading Fe3O4 and achieving optimal mixing and dispersion of Fe3O4 in the RF solution. Variations of the molar ratios of the catalyst (R/C = 50, 100, 150, and 200), water (R/W = 0.04 and 0.05), and Fe3O4 (M/R = 0.01, 0.03, 0.05, 0.1, 0.15, and 0.2), and thermal treatment were applied to evaluate their textural properties and adsorption capacities. Magnetic carbon xerogel monoliths (MXRF600) using indirect sonicat...
Separations
This paper presents a novel family of jarosites with the molecular formula MFe3(SO4)2(OH)6·xH2O; ... more This paper presents a novel family of jarosites with the molecular formula MFe3(SO4)2(OH)6·xH2O; M = Na, K, NH4 that have high efficiency in the adsorption of As(V) and Pb(II) dissolved in water. The jarosites have been prepared by conventional heating at temperatures close to 95 °C for 3 h. The synthesis method was improved and optimized to reduce the time and energy consumption. The improved conventional heating method allowed for the synthesis of Na− and K−jarosites with a yield of up to 97.8 wt.% at 105 and 150 °C, respectively, in 3 h. The Na−, K−, and NH4−jarosites were synthesized at 150 °C in 5 min via a microwave-assisted method, which yielded jarosite crystalline agglomerates with more uniform topography, shape, and size than the conventional method. Both methods allowed the selective synthesis of jarosites. Chemical decomposition of jarosites suspended in water occurred at a pH less than 2 and higher than 10 and temperatures up to 150 °C. In the solid state, the jarosites...
International Journal of Hydrogen Energy, 2023
International Journal of Hydrogen Energy
The composition of soil/sand, soil/vermicompost and soil/zeolite had a good relationships between... more The composition of soil/sand, soil/vermicompost and soil/zeolite had a good relationships between the soil filling percentage and significantly removed FC contents (0.750.20-1.250.60 log) at a ratio of 75/25 (soil/media). The filter media analysis of chemistry, physics, and morphology demonstrated that the effect of soil filling on FC bacteria removal depends on the fine particle size and the increasing of ion charges. The main mechanisms to remove FC are the straining and the adsorption between clay particle and bacteria. However, the IMI of soil/charcoal provokes the highest removal (2.460.29 log) than other media due to its high adsorption capacity following the standard limits in four monitoring weeks.
This research focuses on generating magnetic adsorbents with less expensive precursors, a simple ... more This research focuses on generating magnetic adsorbents with less expensive precursors, a simple and cheap method of subcritical drying for xerogel, and easily recovered from the aqueous medium with magnetic properties for reducing impact of pollutants in the environment. The application of the response surface methodology (RSM) in optimization of As(III) and As(V) adsorption process on carbon xerogel nanocomposites (XMCs) from aqueous solution was proposed in this study under the scheme of a central composite design 23 with a central face. XMCs were synthesized from sol-gel polymerization of a resorcinol-formaldehyde composited with magnetite nanoparticles (MNPs) and carbonized at 600°C for 6 h. MNPs were incorporated into the structure of gels corresponding to the XRD, FTIR and SEM/EDX analysis. The varying stoichiometric of resorcinol/water ratios had a significant effect on the resulting texture and surface chemistry properties. The model obtained by RSM was able to acquire the ...
2019 International Conference on Engineering, Science, and Industrial Applications (ICESI)
Magnetic xerogels (MCs) were prepared by the cross-linking polymerization of resorcinol and forma... more Magnetic xerogels (MCs) were prepared by the cross-linking polymerization of resorcinol and formaldehyde (RF) using the alkaline catalyst and magnetite (Fe3O4). The indirect sonication was applied to distribute magnetite particles in RF aqueous solution to obtain the magnetic adsorbent that could be used as an easier recovery of adsorbent for water treatment. As a result of the characterization by X-ray diffraction and energy dispersive X-ray spectroscopy was confirmed the presence of magnetite into the gel at 1.19% with low molar ratio of magnetite and resorcinol ratio at 0.01. The surface morphology and textural properties of RF gel characterized by field emission scanning electron microscope affect directly with the variation of molar ratio of resorcinol and catalyst (R/C), which were 50, 100 and 200. The behavior of arsenic (As(V)) adsorption by using MCs was studied in groundwater into the ranges of pH from 2.0 to 7.0. The maximum As(V) uptake was on MC prepared with low R/C molar ratio at 50 while R/C at 100 gave the best performance within the application range of pH. Furthermore, the prediction technique based on an adaptive fuzzy rules emulated network is utilized for evaluation the arsenic removal performance.
Water Science and Engineering
Water Supply, 2020
Magnetic xerogels monoliths (MCs) were simultaneously prepared and formed by the cross-linking po... more Magnetic xerogels monoliths (MCs) were simultaneously prepared and formed by the cross-linking polymerization of resorcinol and formaldehyde using the alkaline catalyst and magnetite. The varying of molar ratio of resorcinol and catalyst (R/C) was studied and characterized by isoelectric point (IEP), point of zero charge (pHpzc), scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), N2 adsorption and Fourier transform infrared spectroscopy (FTIR). The result of XRD and EDX confirmed the presence of magnetite into the gel at 1.19% with low molar ratio of magnetite and resorcinol ratio at 0.01. The surface morphology and textural properties of MCs affect directly with SBET, total pore volume and volume of mesopore increase when molar of R/C increases. The behavior of arsenic (As(V)) adsorption by using MCs, was studied in groundwater into the ranges of pH from 2.0 to 7.0. MC50 shows the maximum As(V) uptake and removal were 72 μg/g and 7...
International Journal of Environmental Research, 2013
Current global water shortage and water pollution problem are some of the crucial issues in thewo... more Current global water shortage and water pollution problem are some of the crucial issues in theworld, especially in the arid zones. The wastewater reuse was investigated the efficiency of fecal coliform(FC) removal using the intermittent media infiltration (IMI) with varying soil content and natural porousmedia (sand, zeolite, vermicompost and charcoal), and its prediction was introduced by applying fuzzy rulesemulated network (FREN). The physicochemical properties of the porous media were determined and themechanisms of FC removal were discussed as the effect of fine particle size and increasing of ion charges. The compositions of soil and porous media at a ratio of 75/25, respectively, gave the best performance of FC reduction. The network architecture was constructed by the knowledge regarding to the relation between soil content (25, 50 and 75) and FC removal, and was introduced IF-THEN rules for FREN construction as theirpredicted curves at 20 iterations. The learning rate was ...
Processes, 2021
Arsenic contamination of groundwater is still a global problem due to the toxicity at low dose on... more Arsenic contamination of groundwater is still a global problem due to the toxicity at low dose on human health confirmed by epidemiological studies. Magnetic xerogel monoliths (MXs) were synthesized by the sol-gel polymerization using resorcinol, formaldehyde, alkaline catalyst and magnetite. The varying molar ratios of magnetite and resorcinol (M/R) in the gel were evaluated for As(V) removal from groundwater. The surface chemistry, structure and morphology of MXs related to arsenic adsorption were characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy and point of zero charge. Batch adsorption experiments were carried out to investigate the effects of Fe contents, initial pH and adsorbent dose on As(V) removal performance. The MXs with molar ratio of M/R at 0.15 gave the maximum As(V) adsorption capacity and removal with values of 62.8 µg/g and 86.7%, respectively. The adsorption data were wel...
Environmental Engineering and Management Journal, 2013
The reuse of a wastewater treatment system was investigated using intermittent media infiltration... more The reuse of a wastewater treatment system was investigated using intermittent media infiltration (IMI) to evaluate the fecal coliform (FC) removal efficiency with natural zeolite containing clinoptilolite from the state of San Luis Potosí, Mexico and its zinc-modified form (Zeo-Zn). The municipal wastewater, which was from Saltillo, Coahuila, Mexico, was treated for FC analysis for four months. The physicochemical properties of zeolite were analyzed, and their behavior as filter media for FC removal with an IMI system was studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-Ray fluorescence techniques (XRF). At the conditions under which natural zeolite was treated to functionalize its surface with a bactericide agent (Zn 2+), there were no significant structural and chemical changes in the clinoptilolite contained in the natural zeolite. Thus, Zeo-Zn could be regenerated by treatment with a zinc salt after a long-term IMI process. The use of Zeo-Zn resulted in an average FC removal efficiency (2.99 0.92 log) and FC reduction (99.44 1.04%) that were significant better than those obtained with natural zeolite (approximately 47.44%). Zeo-Zn enhanced the removal of FC in the IMI system more than natural zeolite and thus complied with Mexican regulations for unrestricted reuse during the study period. The study showed that Mexican natural zeolite functionalized with zinc can be used as a disinfectant to achieve the antibacterial effect in an IMI system for wastewater treatment.
Journal of Chemical Technology & Biotechnology, 2019
BACKGROUND Alkaline amorphization of fly ash (FA) and crystallization of the potassium W zeolite ... more BACKGROUND Alkaline amorphization of fly ash (FA) and crystallization of the potassium W zeolite from the amorphous resultant materials was carried out at different scales by a straightforward hydrothermal method. The experimental factors and levels were evaluated during the FA amorphization study by variation of the metallic hydroxide, concentration, temperature and time for the hydrothermal reaction. RESULTS
Computers and Electronics in Agriculture, 2017
In this study, a semi-empirical dynamic model of energy balance was developed to predict temperat... more In this study, a semi-empirical dynamic model of energy balance was developed to predict temperatures (air, plants, greenhouse cover and soil) in a naturally ventilated greenhouse with a polypropylene mulch covering the soil in a Mediterranean climate. The model was validated using experimental data of 5 nonsuccessive periods of 5 days throughout the crop season in the province of Almería (Spain). During the evaluation period, the transmissivity of the cover ranged between 0.44 and 0.80 depending on whitening, and the leaf area index of the tomato crops growing inside the greenhouse varied from L AI = 0.74 to 1.30 m 2 m À2. The model mainly consists of a system of 6 non-linear differential equations of energy conservation at inside air, greenhouse plastic cover, polypropylene mulch and three layers of soil. We used multiple linear regressions to estimate the crop temperature in a simple way that allows a reduction in the number of parameters required as input. The main components of the energy balance in warm climate conditions are the solar radiation, the heat exchanged by natural ventilation and the heat stored in the soil. To improve the estimation of the heat exchanged by ventilation, different discharge coefficients were used for roof C dVR and side openings C dVS. Both coefficients changed throughout the time as a function of the height and opening angle of the windows and of the air velocity across the insect-proof screens. The model also used different wind effect coefficients C w for Northeast or Southwest winds, to take into account the different obstacles (a neighbouring greenhouse at the south and a warehouse at the north). A linear regression of the wind direction angle h w was used as correction function for the volumetric ventilation flux G. The results showed that the accuracy of the model is affected mainly by errors in the cover transmissivity on cloudy days (when diffuse radiation prevails) and errors in the temperature of air exiting the greenhouse on windy days (when hot air stagnated near roof openings, that were closed by the climate controller to avoid wind damage). In general, the results of validation comparing calculated values with those measured on 25 days (with relative root mean square errors below 10%), show sufficient accuracy for the model to be used to estimate air, crop, plastic cover, polypropylene mulch and soil temperatures inside the greenhouse, and as a design tool to optimise the ventilation system characteristics and control settings.
Journal of Water Resource and Protection, 2013
In the "Laguna" region of Coahuila state, Mexico like other places in the world, the groundwater ... more In the "Laguna" region of Coahuila state, Mexico like other places in the world, the groundwater needs to be treated to meet the quality required for human consumption. The study had probed that a Mexican fly ash can be used as a raw material to obtain effective low cost adsorbents for drinking water treatment, as well evaluated the effects of pH, ion coexistence, dose, arsenic (As) concentration and temperature on the As(V) uptake by using P and W modified zeolites (PMOD and WMOD) obtained from a Mexican fly ash. The As(V) adsorption capacity of the WMOD zeolite was not affected by pH and As(V) concentrations in aqueous solution was achieved 0.01 mg/L in the studied pH range; however, the As(V) removal by using PMOD zeolite decreased at high pH values. Carbonate concentration had a negative effect on the As(V) uptake of both zeolites but this effect was higher for the PMOD zeolite. The maximum adsorption capacities (Qmax) were 76.11 and 44.44 mg of As(V)/g of zeolite for the WMOD and the PMOD zeolites, respectively. The adsorption process was endothermic, spontaneous and occurred by chemical exchange. The experimental data were best interpreted by a pseudo-second order kinetic model. The WMOD zeolite showed a higher adsorption capacity and rate than the PMOD even at the highest evaluated As(V) concentration. The adsorption capacity of the regenerated WMOD zeolite was similar to the original zeolite. Because of the high As(V) adsorption capacity, chemical stability and regenerability, the WMOD zeolite is potentially useful as low-cost adsorbent for As(V) removal from aqueous effluents.
Water Science & Technology, 2012
The reclamation of domestic wastewater for irrigation is one alternative approach to solve the wa... more The reclamation of domestic wastewater for irrigation is one alternative approach to solve the water scarcity crisis, but it is essential to control the microbiological quality of wastewater used for irrigation. The removal of thermotolerant coliforms, also known as faecal coliforms (FC), from treated domestic wastewater by intermittent media infiltration (IMI) in column was studied. The columns were filled with natural filter media (soil, soil/charcoal and zinc-modified zeolite, Zeo-Zn), and wastewater, IMI-treated wastewater and disinfected wastewater were compared. The numbers of residual FC on Swiss chard (Beta vulgaris) and in agricultural soil were determined over a 4-month period. The column using Zeo-Zn had a higher FC removal efficiency (2.98 log) than columns with other filter media and disinfection (1.87–2.57 log) due to the bactericidal properties of Zn2+. The treatment of wastewater using Zeo-Zn and disinfection both decreased the accumulation of FC on plants and in soi...
Environmental Engineering and Management Journal, 2016
Water scarcity, the degradation of freshwater resources, and wastewater pollution are reaching cr... more Water scarcity, the degradation of freshwater resources, and wastewater pollution are reaching crisis levels, especially in arid regions of the world. The reuse of wastewater was investigated by using intermittent media infiltration (IMI) to evaluate fecal coliform (FC) removal efficiency. Twelve IMI columns were packed with soil and natural filtering materials (sand, zeolite, vermicompost and charcoal) at percentages of 25, 50 and 75. The municipal wastewater was treated for the FC analysis for four weeks. The chemistry, physics, and morphology of the filter media as related to FC reduction were determined and characterized. Fine particle size and adsorption capacity are important factors for retaining FCs. The mixture of clay soil and filter media in a ratio of 75/25 gave the best performance for FC removal, and the average FC reductions for sand, zeolite, vermicompost and charcoal were 94.4%, 82.2%, 93.8% and 99.6%, respectively. The IMI of soil/charcoal gave a higher log removal (2.19-2.46 log) than the other media, and the effluent complied with Mexican regulations for unrestricted agricultural irrigation. These results showed good performance for FC removal and strengthened the possibility of using reclaimed municipal wastewater in unrestricted irrigation.
World Environmental and Water Resources Congress 2011, 2011
IntechOpen eBooks, May 13, 2024
Arsenic, a widespread contaminant, has become a major public health concern, threatening millions... more Arsenic, a widespread contaminant, has become a major public health concern, threatening millions globally. This study aims to develop magnetic adsorbents for easy recovery from aqueous media to remove arsenic, mitigating its environmental and health impacts. Response surface methodology (RSM) is proposed to optimize the adsorption-desorption process of As(III) and As(V) on carbon xerogel nanocomposites from aqueous solutions. A second-order polynomial model under a central composite design with a central face was employed to optimize arsenic desorption. The model parameters were estimated using least squares. Additionally, a novel linear model approach was employed to develop a second-degree polynomial model for optimizing arsenic adsorption-desorption by analyzing the effects of various factor combinations. RSM's ability to analyze the response variable over a wide range of independent variable values allows it to identify the region where the response variable reaches its optimum value.
Gels
Inorganic arsenic in drinking water from groundwater sources is one of the potential causes of ar... more Inorganic arsenic in drinking water from groundwater sources is one of the potential causes of arsenic-contaminated environments, and it is highly toxic to human health even at low concentrations. The purpose of this study was to develop a magnetic adsorbent capable of removing arsenic from water. Fe3O4-monolithic resorcinol-formaldehyde carbon xerogels are a type of porous material that forms when resorcinol and formaldehyde (RF) react to form a polymer network, which is then cross-linked with magnetite. Sonication-assisted direct and indirect methods were investigated for loading Fe3O4 and achieving optimal mixing and dispersion of Fe3O4 in the RF solution. Variations of the molar ratios of the catalyst (R/C = 50, 100, 150, and 200), water (R/W = 0.04 and 0.05), and Fe3O4 (M/R = 0.01, 0.03, 0.05, 0.1, 0.15, and 0.2), and thermal treatment were applied to evaluate their textural properties and adsorption capacities. Magnetic carbon xerogel monoliths (MXRF600) using indirect sonicat...
Separations
This paper presents a novel family of jarosites with the molecular formula MFe3(SO4)2(OH)6·xH2O; ... more This paper presents a novel family of jarosites with the molecular formula MFe3(SO4)2(OH)6·xH2O; M = Na, K, NH4 that have high efficiency in the adsorption of As(V) and Pb(II) dissolved in water. The jarosites have been prepared by conventional heating at temperatures close to 95 °C for 3 h. The synthesis method was improved and optimized to reduce the time and energy consumption. The improved conventional heating method allowed for the synthesis of Na− and K−jarosites with a yield of up to 97.8 wt.% at 105 and 150 °C, respectively, in 3 h. The Na−, K−, and NH4−jarosites were synthesized at 150 °C in 5 min via a microwave-assisted method, which yielded jarosite crystalline agglomerates with more uniform topography, shape, and size than the conventional method. Both methods allowed the selective synthesis of jarosites. Chemical decomposition of jarosites suspended in water occurred at a pH less than 2 and higher than 10 and temperatures up to 150 °C. In the solid state, the jarosites...
International Journal of Hydrogen Energy, 2023
International Journal of Hydrogen Energy
The composition of soil/sand, soil/vermicompost and soil/zeolite had a good relationships between... more The composition of soil/sand, soil/vermicompost and soil/zeolite had a good relationships between the soil filling percentage and significantly removed FC contents (0.750.20-1.250.60 log) at a ratio of 75/25 (soil/media). The filter media analysis of chemistry, physics, and morphology demonstrated that the effect of soil filling on FC bacteria removal depends on the fine particle size and the increasing of ion charges. The main mechanisms to remove FC are the straining and the adsorption between clay particle and bacteria. However, the IMI of soil/charcoal provokes the highest removal (2.460.29 log) than other media due to its high adsorption capacity following the standard limits in four monitoring weeks.
This research focuses on generating magnetic adsorbents with less expensive precursors, a simple ... more This research focuses on generating magnetic adsorbents with less expensive precursors, a simple and cheap method of subcritical drying for xerogel, and easily recovered from the aqueous medium with magnetic properties for reducing impact of pollutants in the environment. The application of the response surface methodology (RSM) in optimization of As(III) and As(V) adsorption process on carbon xerogel nanocomposites (XMCs) from aqueous solution was proposed in this study under the scheme of a central composite design 23 with a central face. XMCs were synthesized from sol-gel polymerization of a resorcinol-formaldehyde composited with magnetite nanoparticles (MNPs) and carbonized at 600°C for 6 h. MNPs were incorporated into the structure of gels corresponding to the XRD, FTIR and SEM/EDX analysis. The varying stoichiometric of resorcinol/water ratios had a significant effect on the resulting texture and surface chemistry properties. The model obtained by RSM was able to acquire the ...
2019 International Conference on Engineering, Science, and Industrial Applications (ICESI)
Magnetic xerogels (MCs) were prepared by the cross-linking polymerization of resorcinol and forma... more Magnetic xerogels (MCs) were prepared by the cross-linking polymerization of resorcinol and formaldehyde (RF) using the alkaline catalyst and magnetite (Fe3O4). The indirect sonication was applied to distribute magnetite particles in RF aqueous solution to obtain the magnetic adsorbent that could be used as an easier recovery of adsorbent for water treatment. As a result of the characterization by X-ray diffraction and energy dispersive X-ray spectroscopy was confirmed the presence of magnetite into the gel at 1.19% with low molar ratio of magnetite and resorcinol ratio at 0.01. The surface morphology and textural properties of RF gel characterized by field emission scanning electron microscope affect directly with the variation of molar ratio of resorcinol and catalyst (R/C), which were 50, 100 and 200. The behavior of arsenic (As(V)) adsorption by using MCs was studied in groundwater into the ranges of pH from 2.0 to 7.0. The maximum As(V) uptake was on MC prepared with low R/C molar ratio at 50 while R/C at 100 gave the best performance within the application range of pH. Furthermore, the prediction technique based on an adaptive fuzzy rules emulated network is utilized for evaluation the arsenic removal performance.
Water Science and Engineering
Water Supply, 2020
Magnetic xerogels monoliths (MCs) were simultaneously prepared and formed by the cross-linking po... more Magnetic xerogels monoliths (MCs) were simultaneously prepared and formed by the cross-linking polymerization of resorcinol and formaldehyde using the alkaline catalyst and magnetite. The varying of molar ratio of resorcinol and catalyst (R/C) was studied and characterized by isoelectric point (IEP), point of zero charge (pHpzc), scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), N2 adsorption and Fourier transform infrared spectroscopy (FTIR). The result of XRD and EDX confirmed the presence of magnetite into the gel at 1.19% with low molar ratio of magnetite and resorcinol ratio at 0.01. The surface morphology and textural properties of MCs affect directly with SBET, total pore volume and volume of mesopore increase when molar of R/C increases. The behavior of arsenic (As(V)) adsorption by using MCs, was studied in groundwater into the ranges of pH from 2.0 to 7.0. MC50 shows the maximum As(V) uptake and removal were 72 μg/g and 7...
International Journal of Environmental Research, 2013
Current global water shortage and water pollution problem are some of the crucial issues in thewo... more Current global water shortage and water pollution problem are some of the crucial issues in theworld, especially in the arid zones. The wastewater reuse was investigated the efficiency of fecal coliform(FC) removal using the intermittent media infiltration (IMI) with varying soil content and natural porousmedia (sand, zeolite, vermicompost and charcoal), and its prediction was introduced by applying fuzzy rulesemulated network (FREN). The physicochemical properties of the porous media were determined and themechanisms of FC removal were discussed as the effect of fine particle size and increasing of ion charges. The compositions of soil and porous media at a ratio of 75/25, respectively, gave the best performance of FC reduction. The network architecture was constructed by the knowledge regarding to the relation between soil content (25, 50 and 75) and FC removal, and was introduced IF-THEN rules for FREN construction as theirpredicted curves at 20 iterations. The learning rate was ...
Processes, 2021
Arsenic contamination of groundwater is still a global problem due to the toxicity at low dose on... more Arsenic contamination of groundwater is still a global problem due to the toxicity at low dose on human health confirmed by epidemiological studies. Magnetic xerogel monoliths (MXs) were synthesized by the sol-gel polymerization using resorcinol, formaldehyde, alkaline catalyst and magnetite. The varying molar ratios of magnetite and resorcinol (M/R) in the gel were evaluated for As(V) removal from groundwater. The surface chemistry, structure and morphology of MXs related to arsenic adsorption were characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy and point of zero charge. Batch adsorption experiments were carried out to investigate the effects of Fe contents, initial pH and adsorbent dose on As(V) removal performance. The MXs with molar ratio of M/R at 0.15 gave the maximum As(V) adsorption capacity and removal with values of 62.8 µg/g and 86.7%, respectively. The adsorption data were wel...
Environmental Engineering and Management Journal, 2013
The reuse of a wastewater treatment system was investigated using intermittent media infiltration... more The reuse of a wastewater treatment system was investigated using intermittent media infiltration (IMI) to evaluate the fecal coliform (FC) removal efficiency with natural zeolite containing clinoptilolite from the state of San Luis Potosí, Mexico and its zinc-modified form (Zeo-Zn). The municipal wastewater, which was from Saltillo, Coahuila, Mexico, was treated for FC analysis for four months. The physicochemical properties of zeolite were analyzed, and their behavior as filter media for FC removal with an IMI system was studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-Ray fluorescence techniques (XRF). At the conditions under which natural zeolite was treated to functionalize its surface with a bactericide agent (Zn 2+), there were no significant structural and chemical changes in the clinoptilolite contained in the natural zeolite. Thus, Zeo-Zn could be regenerated by treatment with a zinc salt after a long-term IMI process. The use of Zeo-Zn resulted in an average FC removal efficiency (2.99 0.92 log) and FC reduction (99.44 1.04%) that were significant better than those obtained with natural zeolite (approximately 47.44%). Zeo-Zn enhanced the removal of FC in the IMI system more than natural zeolite and thus complied with Mexican regulations for unrestricted reuse during the study period. The study showed that Mexican natural zeolite functionalized with zinc can be used as a disinfectant to achieve the antibacterial effect in an IMI system for wastewater treatment.
Journal of Chemical Technology & Biotechnology, 2019
BACKGROUND Alkaline amorphization of fly ash (FA) and crystallization of the potassium W zeolite ... more BACKGROUND Alkaline amorphization of fly ash (FA) and crystallization of the potassium W zeolite from the amorphous resultant materials was carried out at different scales by a straightforward hydrothermal method. The experimental factors and levels were evaluated during the FA amorphization study by variation of the metallic hydroxide, concentration, temperature and time for the hydrothermal reaction. RESULTS
Computers and Electronics in Agriculture, 2017
In this study, a semi-empirical dynamic model of energy balance was developed to predict temperat... more In this study, a semi-empirical dynamic model of energy balance was developed to predict temperatures (air, plants, greenhouse cover and soil) in a naturally ventilated greenhouse with a polypropylene mulch covering the soil in a Mediterranean climate. The model was validated using experimental data of 5 nonsuccessive periods of 5 days throughout the crop season in the province of Almería (Spain). During the evaluation period, the transmissivity of the cover ranged between 0.44 and 0.80 depending on whitening, and the leaf area index of the tomato crops growing inside the greenhouse varied from L AI = 0.74 to 1.30 m 2 m À2. The model mainly consists of a system of 6 non-linear differential equations of energy conservation at inside air, greenhouse plastic cover, polypropylene mulch and three layers of soil. We used multiple linear regressions to estimate the crop temperature in a simple way that allows a reduction in the number of parameters required as input. The main components of the energy balance in warm climate conditions are the solar radiation, the heat exchanged by natural ventilation and the heat stored in the soil. To improve the estimation of the heat exchanged by ventilation, different discharge coefficients were used for roof C dVR and side openings C dVS. Both coefficients changed throughout the time as a function of the height and opening angle of the windows and of the air velocity across the insect-proof screens. The model also used different wind effect coefficients C w for Northeast or Southwest winds, to take into account the different obstacles (a neighbouring greenhouse at the south and a warehouse at the north). A linear regression of the wind direction angle h w was used as correction function for the volumetric ventilation flux G. The results showed that the accuracy of the model is affected mainly by errors in the cover transmissivity on cloudy days (when diffuse radiation prevails) and errors in the temperature of air exiting the greenhouse on windy days (when hot air stagnated near roof openings, that were closed by the climate controller to avoid wind damage). In general, the results of validation comparing calculated values with those measured on 25 days (with relative root mean square errors below 10%), show sufficient accuracy for the model to be used to estimate air, crop, plastic cover, polypropylene mulch and soil temperatures inside the greenhouse, and as a design tool to optimise the ventilation system characteristics and control settings.
Journal of Water Resource and Protection, 2013
In the "Laguna" region of Coahuila state, Mexico like other places in the world, the groundwater ... more In the "Laguna" region of Coahuila state, Mexico like other places in the world, the groundwater needs to be treated to meet the quality required for human consumption. The study had probed that a Mexican fly ash can be used as a raw material to obtain effective low cost adsorbents for drinking water treatment, as well evaluated the effects of pH, ion coexistence, dose, arsenic (As) concentration and temperature on the As(V) uptake by using P and W modified zeolites (PMOD and WMOD) obtained from a Mexican fly ash. The As(V) adsorption capacity of the WMOD zeolite was not affected by pH and As(V) concentrations in aqueous solution was achieved 0.01 mg/L in the studied pH range; however, the As(V) removal by using PMOD zeolite decreased at high pH values. Carbonate concentration had a negative effect on the As(V) uptake of both zeolites but this effect was higher for the PMOD zeolite. The maximum adsorption capacities (Qmax) were 76.11 and 44.44 mg of As(V)/g of zeolite for the WMOD and the PMOD zeolites, respectively. The adsorption process was endothermic, spontaneous and occurred by chemical exchange. The experimental data were best interpreted by a pseudo-second order kinetic model. The WMOD zeolite showed a higher adsorption capacity and rate than the PMOD even at the highest evaluated As(V) concentration. The adsorption capacity of the regenerated WMOD zeolite was similar to the original zeolite. Because of the high As(V) adsorption capacity, chemical stability and regenerability, the WMOD zeolite is potentially useful as low-cost adsorbent for As(V) removal from aqueous effluents.
Water Science & Technology, 2012
The reclamation of domestic wastewater for irrigation is one alternative approach to solve the wa... more The reclamation of domestic wastewater for irrigation is one alternative approach to solve the water scarcity crisis, but it is essential to control the microbiological quality of wastewater used for irrigation. The removal of thermotolerant coliforms, also known as faecal coliforms (FC), from treated domestic wastewater by intermittent media infiltration (IMI) in column was studied. The columns were filled with natural filter media (soil, soil/charcoal and zinc-modified zeolite, Zeo-Zn), and wastewater, IMI-treated wastewater and disinfected wastewater were compared. The numbers of residual FC on Swiss chard (Beta vulgaris) and in agricultural soil were determined over a 4-month period. The column using Zeo-Zn had a higher FC removal efficiency (2.98 log) than columns with other filter media and disinfection (1.87–2.57 log) due to the bactericidal properties of Zn2+. The treatment of wastewater using Zeo-Zn and disinfection both decreased the accumulation of FC on plants and in soi...
Environmental Engineering and Management Journal, 2016
Water scarcity, the degradation of freshwater resources, and wastewater pollution are reaching cr... more Water scarcity, the degradation of freshwater resources, and wastewater pollution are reaching crisis levels, especially in arid regions of the world. The reuse of wastewater was investigated by using intermittent media infiltration (IMI) to evaluate fecal coliform (FC) removal efficiency. Twelve IMI columns were packed with soil and natural filtering materials (sand, zeolite, vermicompost and charcoal) at percentages of 25, 50 and 75. The municipal wastewater was treated for the FC analysis for four weeks. The chemistry, physics, and morphology of the filter media as related to FC reduction were determined and characterized. Fine particle size and adsorption capacity are important factors for retaining FCs. The mixture of clay soil and filter media in a ratio of 75/25 gave the best performance for FC removal, and the average FC reductions for sand, zeolite, vermicompost and charcoal were 94.4%, 82.2%, 93.8% and 99.6%, respectively. The IMI of soil/charcoal gave a higher log removal (2.19-2.46 log) than the other media, and the effluent complied with Mexican regulations for unrestricted agricultural irrigation. These results showed good performance for FC removal and strengthened the possibility of using reclaimed municipal wastewater in unrestricted irrigation.
World Environmental and Water Resources Congress 2011, 2011