chandrasekar srinivasakannan - Academia.edu (original) (raw)

Papers by chandrasekar srinivasakannan

Research paper thumbnail of Gasification Kinetics of Date palm seed using Carbon Dioxide

International Journal of Environmental Research, 2013

Gasification is a well-known reaction owing to its relevance to generation of sustainable energyf... more Gasification is a well-known reaction owing to its relevance to generation of sustainable energyfrom biomass and development of porous carbons. The present paper attempts to experimentally investigate the kinetics of palm shell char gasification using carbon dioxide (CO2) in a controlled environment using Thermo Gravimetric Analyzer (TGA) at temperatures ranging from 800 to1000°C. A relevant kinetic model representing the experimental data was identified by fitting the experimental data with popular semi empirical kinetic models such as Linear Model (LM), Volume Reaction Model (VRM), Shrinking Core Model (SCM), and Random Pore Model (RPM). The model kinetic parameters were evaluated by minimizing the sum of root mean square error (RMSE). Among the models tested the RPM exhibited very close adherence to the experimental data evidenced from the minimum RMSE of 0.0046. The ability of the RPM model to represent the gasification kinetics was attributed to its ability to account for the p...

Research paper thumbnail of Selective removal of diethanolamine from methyldiethanolamine solution using chemically reduced single-layer graphene and activated carbon

Separation Science and Technology, 2018

The adsorption capacity of chemically reduced graphene (CRG) in selective removal of diethanolami... more The adsorption capacity of chemically reduced graphene (CRG) in selective removal of diethanolamine (DEA) from a mixture of methyldiethanolamine (MDEA) in aqueous solutions was evaluated and compared with commercially available activated carbons using batch studies. Four equilibrium isotherm models such as Langmuir, Freundlich, Temkin, and Dubinin-Radushkevish and three different kinetics models such as Pseudo-first order, Pseudo-second order and Intra-particle diffusion were applied. The maximum uptake capacity for DEA using CRG at 296 K (250.0 mg/g) was high compared to two selected activated carbons (1.05 and 0.559 mg/g). The adsorption of DEA was found to be spontaneous and endothermic process with all the adsorbents.

Research paper thumbnail of UV照射下の金属酸化物担持多孔質炭素マトリックスにより触媒されたフェノール分解【JST・京大機械翻訳】

Journal of water process engineering, 2019

Research paper thumbnail of Treatment of dye house effluent using batch and continuous electrochemical reactor

Research paper thumbnail of 銅粉末のマイクロ波融解の特性に関する研究【Powered by NICT】

Journal of Alloys and Compounds, 2017

Research paper thumbnail of Computer Simulation of Catalytic Oxidation of Gaseous Ammonia in Bubbling Fluidized Bed

For long, ammonia has been branded as a harmful acid pollutant causing irreversible damage to the... more For long, ammonia has been branded as a harmful acid pollutant causing irreversible damage to the environment. Unlike other pollutants like nitrogen oxides (NOx) and sulphur oxides (SOx), ammonia causes acidification to the environment in a more complex and indirect way. The sequence of reactions between ammonia and acidic aerosols followed with microorganisms to form acidic HNO3 has been well documented in the literature.1,2 The sources of ammonia could be traced to various industries, including fertilizer manufacturing industry, coke manufacture, fossil fuel combustion, and biomass gasification. Moreover, ammonia is not only emitted by direct sources (process) but also through indirect means such as control technologies of other pollutants, especially nitrogen oxides (NOx). Selective catalytic reduction (SCR) is one of the main technologies employed for controlling NOx emissions. A significant amount of ammonia is added to the SCR process to convert NOx to nitrogen according to th...

Research paper thumbnail of Optimization of Hydrous Ferrous Sulfate Dehydration by Microwave Heating Using Response Surface Methodology

Journal of Microwave Power and Electromagnetic Energy, 2012

The work relates to assessing the ability of the microwave for dehydration of large amount of was... more The work relates to assessing the ability of the microwave for dehydration of large amount of waste hydrous ferrous sulfate generated from the titanium pigment process industry. The popular process optimization tool of response surface methodology with central composite design was adopted to estimate the effect of dehydration. The process variables were chosen to be power input, duration of heating and the bed thickness, while the response variable being the weight loss. An increase in all the three process variables were found to significantly increase the weight loss, while the effect of interaction among the parameters were found to be insignificant. The optimized process conditions that contribute to the maximum weight loss were identified to be a power input of 960 W, duration of heating of 14 min and bed thickness of 5 cm, resulting in a weight loss of 31.44%. The validity of the optimization process was tested with the repeat runs at optimized conditions.

Research paper thumbnail of Cu‐CuOナノ複合材料の合成ミクロ反応器とその応用光触媒分解の原因となる【Powered by NICT】

Research paper thumbnail of An analysis of modeling moisture diffusion from solids in fluidized beds

Research paper thumbnail of 酸性チオ尿素を用いた焼結ダストからの銀の超音波増強と従来の浸出の比較【Powered by NICT】

Research paper thumbnail of Polymer Recovery through Selective Dissolution of Co-mingled Post-Consumer Waste Plastics

Progress in Rubber, Plastics and Recycling Technology, 2017

It still remains a challenge to the recycling industry to develop an efficient and economical lar... more It still remains a challenge to the recycling industry to develop an efficient and economical large-scale plastic waste recycling system, in spite of growing environmental concerns in waste disposal. Selective dissolution and precipitation (SDP) is a mechanical recycling technique that eliminates pre-sorting of mixed waste plastics and recycling polymer of high-grade quality. In this preliminary investigation, recycling of a comingled post-consumer waste plastic mixture of low-density polyethylene (LDPE), polystyrene (PS), high-density polyethylene (HDPE), and polyethylene terephthalate (PETE) using a lab-scale SDP setup was examined. A few experimental runs performed on the representative samples using Xylene/Toluene as solvents and acetone/2-propanol as anti-solvents demonstrated the sorting and recycling efficiency of this technique. FT-IR analysis of the reclaimed products revealed that the structural properties being very similar to virgin materials.

Research paper thumbnail of Optimization of microwave-assisted manganese leaching from electrolyte manganese residue

Green Processing and Synthesis, 2019

The process optimization of microwave assisted leaching of manganese from electrolytic manganese ... more The process optimization of microwave assisted leaching of manganese from electrolytic manganese residue (EMR) was conducted. The Box-Behnken design (BBD) was utilized to determine the number of experiments as well as to assess the effect of the main leaching parameters, including the reaction temperature, reaction time, concentration of sulfuric acid and dosage of citric acid. A quadratic model was found to best fit the experimental data and was utilized to optimize the process parameters to maximize the percentage manganese recovery. 3-D response surface plots and contour plots were generated utilizing mathematical models to understand the effect of variables as well as to identify the optimal conditions. The optimum conditions of microwave assisted leaching were: temperature of 76°C, time of 55 min, H2SO4 concentration of 0.76 mol·L-1, dosage of citric acid of 3.51 mg/g. Under these conditions, the percentage manganese recovery higher than 90% could be achieved.

Research paper thumbnail of Electroless copper plating of tungsten powders and preparation of WCu20 composites by microwave sintering

Journal of Alloys and Compounds, 2018

Research paper thumbnail of Preparation and application of phosphinic acid functionalized nanosilica for the effective removal of mercury (II) in aqueous solutions

Journal of Sol-Gel Science and Technology, 2018

AbstractA novel adsorbent was synthesized by functionalizing nanosilica with phosphinic acid grou... more AbstractA novel adsorbent was synthesized by functionalizing nanosilica with phosphinic acid groups for the removal of mercury ions from aqueous solutions. The synthesized absorbent was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM) and thermogravimetric analysis (TGA). Meanwhile, the effects of initial pH, contact time and initial mercury ions concentration on the removal of mercury ions from aqueous solutions were investigated by batch adsorption experiments. The results showed that the removal rate reached 99.11% and the maximum adsorption capacity was up to 274.32 mg/g at pH 2 and the equilibrium time of adsorption was about 1 h. The absorbent presented good selectivity for mercury ions among Zn(II), Ni(II), Mn(II) and Ge(IIII). Moreover, the obtained adsorbent has good reusability and the absorbability decreased only from 98.76 to 94.75% after five cycles. Besides, the adsorption isotherms fitted well to the Langmuir isotherm model and adsorption kinetics followed the pseudo-second-order model. The removal mechanism of mercury via phosphinic acid-functionalized silica nanoparticles was chelation interaction. All the experimental data indicated that the phosphinic acid-functionalized silica nanoparticles are very promising in removal of mercury ions from aqueous solutions. A novel adsorbent was synthesized by functionalizing nanosilica with phosphinic acid groups for the removal of mercury ions from aqueous solutions. The adsorbent presented good selectivity and reusability. The removal mechanism is chelation interaction between mercury ions and PA-SNPs.HighlightsA new adsorbent was prepared via modifying nanosilica with phosphinic acid groupsThe adsorbent exhibits an excellent selectivity for mercury ionsThe adsorbent showed a maximum adsorption capacity of 274.32 mg/g for mercury ions under pH 2The removal mechanism was chelation interaction.

Research paper thumbnail of Characterization of the interaction of rare earth elements with P507 in a microfluidic extraction system using spectroscopic analysis

Chemical Engineering Journal, 2019

Abstract An attempt to characterize the interaction of rare earth elements with P507 in a microfl... more Abstract An attempt to characterize the interaction of rare earth elements with P507 in a microfluidic extraction system containing lactic acid as complexing agent is made using spectroscopic (FT-IR, UV–Vis, NMR and MS) analysis. The role of lactic acid in the extraction process is analyzed. The extraction mechanism confirmed that lactic acid does not involve in the extraction reaction. A comparative analysis of the composition of the extracts using FT-IR, UV–Vis, NMR and MS methods, indicates that the extracted complexes of rare earth ions located in the center is formed by the cation exchange process between P O H and RE3+, and coordination process between P O and RE3+.

Research paper thumbnail of Microfluidic solvent extraction of Ce (III) and Pr (III) from a chloride solution using EHEHPA (P507) in a serpentine microreactor

Hydrometallurgy, 2018

Abstract Extractive and separation of Pr/Ce using a Y-junction serpentine microreactor, with 2-et... more Abstract Extractive and separation of Pr/Ce using a Y-junction serpentine microreactor, with 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester (EHEHPA, P507), has been investigated. The results clearly indicate separation factor of Pr/Ce (> 3) is to be higher in the microfluidic extraction as compared to separation factor of around 2 to 3 for batch systems. The optimized residence time of 12 s in micro-flow is much less than that in batch system (≅ 300 s). The extraction rates for Pr and Ce are found to match first order kinetics with the rate constants being 0.2649 s− 1 and 0.2279 s− 1, respectively, which are > 20 times higher than those for batch extraction. The volumetric mass transfer coefficients (KLa) for various operating conditions vary between 0.007 and 0.57 s− 1, which decrease with increase in channel size (channel width and length). The experimentally mass transfer coefficients are compared with those with conventional extractors such as mixer settler and centrifugal extractors.

Research paper thumbnail of Investigation on the recovery of gold and silver from cyanide tailings using chlorination roasting process

Journal of Alloys and Compounds, 2018

Abstract In this work, a chlorination roasting method for the extraction of precious metals (gold... more Abstract In this work, a chlorination roasting method for the extraction of precious metals (gold and silver) from the cyanide tailings (CT) was investigated. The decomposition mechanism of the CaCl2 used as chloride agent was presented during the chlorination roasting. The Au and Ag recovery as high as 91.6% and 54.7% under the optimum experiment conditions would be achieved. The optimal process conditions were identified to be a CaCl2 content 4%, chlorination temperature 1323 K and chlorination duration of 2 h. The microstructures of CT before and after roasting were examined by using scanning electron microscopy (SEM), and the volatilization process of the chloride of Au and Ag was assessed. The chlorination behaviors of all the phases in the CT in air atmosphere was analyzed using the thermogravimetric analysis (TGA), and the phase transformation of the main phase during roasting were analyzed by using X-ray diffraction (XRD). The chlorination roasting process shows unique advantage for treating the secondary sources of CT, additionally being environmentally benign.

Research paper thumbnail of Preparation of magnesium silicate/carbon composite for adsorption of rhodamine B

RSC Advances, 2018

The surface area and pore structure, electrostatic interaction and functional groups are the main... more The surface area and pore structure, electrostatic interaction and functional groups are the main adsorption mechanisms.

Research paper thumbnail of Effect of microwave heating on the microstructures and kinetics of carbothermal reduction of pyrolusite ore

Advanced Powder Technology, 2018

The paper considers a new design of the movable vibrating screen feeder KVG-1PS designed for the ... more The paper considers a new design of the movable vibrating screen feeder KVG-1PS designed for the reception and transfer of rocks and ores in conveyor complexes of cyclic-and-continuous technology in open-cast mining. It contains the results of design analysis of the new mining machine. The paper represents the technique of establishing the main parameters and the calculation of the movable vibrating feeder on the basis of a cascade shock-absorbing system at the representation of the machine within a three-mass oscillatory system.

Research paper thumbnail of Metal-organic framework/graphene oxide composite fillers in mixed-matrix membranes for CO 2 separation

Materials Chemistry and Physics, 2018

Abstract Mixed-matrix membranes (MMMs) comprising of inorganic fillers dispersed in an organic ma... more Abstract Mixed-matrix membranes (MMMs) comprising of inorganic fillers dispersed in an organic matrix gather increased attention for separating gas mixtures due to potential for enhancement in separation selectivity, throughput, and material robustness. In the present study, ZIF-8 metal-organic framework (MOF) and ZIF-8/graphene oxide (GO) hybrid nanofillers were developed and incorporated into polysulfone (PSF) matrix. The fillers and the resulting MMMs were evaluated for their structural, morphological, and sorption characteristics, while the prepared membranes were tested for their permeation and selectivity properties for CO2, N2 and CH4. It is highlighted that, compared to the pristine PSF membrane, the PSF+(ZIF-8/GO) MMMs showed both enhanced CO2 permeability (up to an increase of 87%), and selectivity (up to an increase of 61% for the CO2/CH4 pair). In addition, the selectivity for the PSF+(ZIF-8/GO) MMM was increased by up to 7-fold compared to that of the PSF + ZIF-8 MMM. Based on the results reported, composite fillers combining the functionality of MOFs and GO have the potential to tune and boost the performance of polymeric membranes for CO2 separation from hydrocarbon gases, flue gas, and related gas mixtures.

Research paper thumbnail of Gasification Kinetics of Date palm seed using Carbon Dioxide

International Journal of Environmental Research, 2013

Gasification is a well-known reaction owing to its relevance to generation of sustainable energyf... more Gasification is a well-known reaction owing to its relevance to generation of sustainable energyfrom biomass and development of porous carbons. The present paper attempts to experimentally investigate the kinetics of palm shell char gasification using carbon dioxide (CO2) in a controlled environment using Thermo Gravimetric Analyzer (TGA) at temperatures ranging from 800 to1000°C. A relevant kinetic model representing the experimental data was identified by fitting the experimental data with popular semi empirical kinetic models such as Linear Model (LM), Volume Reaction Model (VRM), Shrinking Core Model (SCM), and Random Pore Model (RPM). The model kinetic parameters were evaluated by minimizing the sum of root mean square error (RMSE). Among the models tested the RPM exhibited very close adherence to the experimental data evidenced from the minimum RMSE of 0.0046. The ability of the RPM model to represent the gasification kinetics was attributed to its ability to account for the p...

Research paper thumbnail of Selective removal of diethanolamine from methyldiethanolamine solution using chemically reduced single-layer graphene and activated carbon

Separation Science and Technology, 2018

The adsorption capacity of chemically reduced graphene (CRG) in selective removal of diethanolami... more The adsorption capacity of chemically reduced graphene (CRG) in selective removal of diethanolamine (DEA) from a mixture of methyldiethanolamine (MDEA) in aqueous solutions was evaluated and compared with commercially available activated carbons using batch studies. Four equilibrium isotherm models such as Langmuir, Freundlich, Temkin, and Dubinin-Radushkevish and three different kinetics models such as Pseudo-first order, Pseudo-second order and Intra-particle diffusion were applied. The maximum uptake capacity for DEA using CRG at 296 K (250.0 mg/g) was high compared to two selected activated carbons (1.05 and 0.559 mg/g). The adsorption of DEA was found to be spontaneous and endothermic process with all the adsorbents.

Research paper thumbnail of UV照射下の金属酸化物担持多孔質炭素マトリックスにより触媒されたフェノール分解【JST・京大機械翻訳】

Journal of water process engineering, 2019

Research paper thumbnail of Treatment of dye house effluent using batch and continuous electrochemical reactor

Research paper thumbnail of 銅粉末のマイクロ波融解の特性に関する研究【Powered by NICT】

Journal of Alloys and Compounds, 2017

Research paper thumbnail of Computer Simulation of Catalytic Oxidation of Gaseous Ammonia in Bubbling Fluidized Bed

For long, ammonia has been branded as a harmful acid pollutant causing irreversible damage to the... more For long, ammonia has been branded as a harmful acid pollutant causing irreversible damage to the environment. Unlike other pollutants like nitrogen oxides (NOx) and sulphur oxides (SOx), ammonia causes acidification to the environment in a more complex and indirect way. The sequence of reactions between ammonia and acidic aerosols followed with microorganisms to form acidic HNO3 has been well documented in the literature.1,2 The sources of ammonia could be traced to various industries, including fertilizer manufacturing industry, coke manufacture, fossil fuel combustion, and biomass gasification. Moreover, ammonia is not only emitted by direct sources (process) but also through indirect means such as control technologies of other pollutants, especially nitrogen oxides (NOx). Selective catalytic reduction (SCR) is one of the main technologies employed for controlling NOx emissions. A significant amount of ammonia is added to the SCR process to convert NOx to nitrogen according to th...

Research paper thumbnail of Optimization of Hydrous Ferrous Sulfate Dehydration by Microwave Heating Using Response Surface Methodology

Journal of Microwave Power and Electromagnetic Energy, 2012

The work relates to assessing the ability of the microwave for dehydration of large amount of was... more The work relates to assessing the ability of the microwave for dehydration of large amount of waste hydrous ferrous sulfate generated from the titanium pigment process industry. The popular process optimization tool of response surface methodology with central composite design was adopted to estimate the effect of dehydration. The process variables were chosen to be power input, duration of heating and the bed thickness, while the response variable being the weight loss. An increase in all the three process variables were found to significantly increase the weight loss, while the effect of interaction among the parameters were found to be insignificant. The optimized process conditions that contribute to the maximum weight loss were identified to be a power input of 960 W, duration of heating of 14 min and bed thickness of 5 cm, resulting in a weight loss of 31.44%. The validity of the optimization process was tested with the repeat runs at optimized conditions.

Research paper thumbnail of Cu‐CuOナノ複合材料の合成ミクロ反応器とその応用光触媒分解の原因となる【Powered by NICT】

Research paper thumbnail of An analysis of modeling moisture diffusion from solids in fluidized beds

Research paper thumbnail of 酸性チオ尿素を用いた焼結ダストからの銀の超音波増強と従来の浸出の比較【Powered by NICT】

Research paper thumbnail of Polymer Recovery through Selective Dissolution of Co-mingled Post-Consumer Waste Plastics

Progress in Rubber, Plastics and Recycling Technology, 2017

It still remains a challenge to the recycling industry to develop an efficient and economical lar... more It still remains a challenge to the recycling industry to develop an efficient and economical large-scale plastic waste recycling system, in spite of growing environmental concerns in waste disposal. Selective dissolution and precipitation (SDP) is a mechanical recycling technique that eliminates pre-sorting of mixed waste plastics and recycling polymer of high-grade quality. In this preliminary investigation, recycling of a comingled post-consumer waste plastic mixture of low-density polyethylene (LDPE), polystyrene (PS), high-density polyethylene (HDPE), and polyethylene terephthalate (PETE) using a lab-scale SDP setup was examined. A few experimental runs performed on the representative samples using Xylene/Toluene as solvents and acetone/2-propanol as anti-solvents demonstrated the sorting and recycling efficiency of this technique. FT-IR analysis of the reclaimed products revealed that the structural properties being very similar to virgin materials.

Research paper thumbnail of Optimization of microwave-assisted manganese leaching from electrolyte manganese residue

Green Processing and Synthesis, 2019

The process optimization of microwave assisted leaching of manganese from electrolytic manganese ... more The process optimization of microwave assisted leaching of manganese from electrolytic manganese residue (EMR) was conducted. The Box-Behnken design (BBD) was utilized to determine the number of experiments as well as to assess the effect of the main leaching parameters, including the reaction temperature, reaction time, concentration of sulfuric acid and dosage of citric acid. A quadratic model was found to best fit the experimental data and was utilized to optimize the process parameters to maximize the percentage manganese recovery. 3-D response surface plots and contour plots were generated utilizing mathematical models to understand the effect of variables as well as to identify the optimal conditions. The optimum conditions of microwave assisted leaching were: temperature of 76°C, time of 55 min, H2SO4 concentration of 0.76 mol·L-1, dosage of citric acid of 3.51 mg/g. Under these conditions, the percentage manganese recovery higher than 90% could be achieved.

Research paper thumbnail of Electroless copper plating of tungsten powders and preparation of WCu20 composites by microwave sintering

Journal of Alloys and Compounds, 2018

Research paper thumbnail of Preparation and application of phosphinic acid functionalized nanosilica for the effective removal of mercury (II) in aqueous solutions

Journal of Sol-Gel Science and Technology, 2018

AbstractA novel adsorbent was synthesized by functionalizing nanosilica with phosphinic acid grou... more AbstractA novel adsorbent was synthesized by functionalizing nanosilica with phosphinic acid groups for the removal of mercury ions from aqueous solutions. The synthesized absorbent was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM) and thermogravimetric analysis (TGA). Meanwhile, the effects of initial pH, contact time and initial mercury ions concentration on the removal of mercury ions from aqueous solutions were investigated by batch adsorption experiments. The results showed that the removal rate reached 99.11% and the maximum adsorption capacity was up to 274.32 mg/g at pH 2 and the equilibrium time of adsorption was about 1 h. The absorbent presented good selectivity for mercury ions among Zn(II), Ni(II), Mn(II) and Ge(IIII). Moreover, the obtained adsorbent has good reusability and the absorbability decreased only from 98.76 to 94.75% after five cycles. Besides, the adsorption isotherms fitted well to the Langmuir isotherm model and adsorption kinetics followed the pseudo-second-order model. The removal mechanism of mercury via phosphinic acid-functionalized silica nanoparticles was chelation interaction. All the experimental data indicated that the phosphinic acid-functionalized silica nanoparticles are very promising in removal of mercury ions from aqueous solutions. A novel adsorbent was synthesized by functionalizing nanosilica with phosphinic acid groups for the removal of mercury ions from aqueous solutions. The adsorbent presented good selectivity and reusability. The removal mechanism is chelation interaction between mercury ions and PA-SNPs.HighlightsA new adsorbent was prepared via modifying nanosilica with phosphinic acid groupsThe adsorbent exhibits an excellent selectivity for mercury ionsThe adsorbent showed a maximum adsorption capacity of 274.32 mg/g for mercury ions under pH 2The removal mechanism was chelation interaction.

Research paper thumbnail of Characterization of the interaction of rare earth elements with P507 in a microfluidic extraction system using spectroscopic analysis

Chemical Engineering Journal, 2019

Abstract An attempt to characterize the interaction of rare earth elements with P507 in a microfl... more Abstract An attempt to characterize the interaction of rare earth elements with P507 in a microfluidic extraction system containing lactic acid as complexing agent is made using spectroscopic (FT-IR, UV–Vis, NMR and MS) analysis. The role of lactic acid in the extraction process is analyzed. The extraction mechanism confirmed that lactic acid does not involve in the extraction reaction. A comparative analysis of the composition of the extracts using FT-IR, UV–Vis, NMR and MS methods, indicates that the extracted complexes of rare earth ions located in the center is formed by the cation exchange process between P O H and RE3+, and coordination process between P O and RE3+.

Research paper thumbnail of Microfluidic solvent extraction of Ce (III) and Pr (III) from a chloride solution using EHEHPA (P507) in a serpentine microreactor

Hydrometallurgy, 2018

Abstract Extractive and separation of Pr/Ce using a Y-junction serpentine microreactor, with 2-et... more Abstract Extractive and separation of Pr/Ce using a Y-junction serpentine microreactor, with 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester (EHEHPA, P507), has been investigated. The results clearly indicate separation factor of Pr/Ce (> 3) is to be higher in the microfluidic extraction as compared to separation factor of around 2 to 3 for batch systems. The optimized residence time of 12 s in micro-flow is much less than that in batch system (≅ 300 s). The extraction rates for Pr and Ce are found to match first order kinetics with the rate constants being 0.2649 s− 1 and 0.2279 s− 1, respectively, which are > 20 times higher than those for batch extraction. The volumetric mass transfer coefficients (KLa) for various operating conditions vary between 0.007 and 0.57 s− 1, which decrease with increase in channel size (channel width and length). The experimentally mass transfer coefficients are compared with those with conventional extractors such as mixer settler and centrifugal extractors.

Research paper thumbnail of Investigation on the recovery of gold and silver from cyanide tailings using chlorination roasting process

Journal of Alloys and Compounds, 2018

Abstract In this work, a chlorination roasting method for the extraction of precious metals (gold... more Abstract In this work, a chlorination roasting method for the extraction of precious metals (gold and silver) from the cyanide tailings (CT) was investigated. The decomposition mechanism of the CaCl2 used as chloride agent was presented during the chlorination roasting. The Au and Ag recovery as high as 91.6% and 54.7% under the optimum experiment conditions would be achieved. The optimal process conditions were identified to be a CaCl2 content 4%, chlorination temperature 1323 K and chlorination duration of 2 h. The microstructures of CT before and after roasting were examined by using scanning electron microscopy (SEM), and the volatilization process of the chloride of Au and Ag was assessed. The chlorination behaviors of all the phases in the CT in air atmosphere was analyzed using the thermogravimetric analysis (TGA), and the phase transformation of the main phase during roasting were analyzed by using X-ray diffraction (XRD). The chlorination roasting process shows unique advantage for treating the secondary sources of CT, additionally being environmentally benign.

Research paper thumbnail of Preparation of magnesium silicate/carbon composite for adsorption of rhodamine B

RSC Advances, 2018

The surface area and pore structure, electrostatic interaction and functional groups are the main... more The surface area and pore structure, electrostatic interaction and functional groups are the main adsorption mechanisms.

Research paper thumbnail of Effect of microwave heating on the microstructures and kinetics of carbothermal reduction of pyrolusite ore

Advanced Powder Technology, 2018

The paper considers a new design of the movable vibrating screen feeder KVG-1PS designed for the ... more The paper considers a new design of the movable vibrating screen feeder KVG-1PS designed for the reception and transfer of rocks and ores in conveyor complexes of cyclic-and-continuous technology in open-cast mining. It contains the results of design analysis of the new mining machine. The paper represents the technique of establishing the main parameters and the calculation of the movable vibrating feeder on the basis of a cascade shock-absorbing system at the representation of the machine within a three-mass oscillatory system.

Research paper thumbnail of Metal-organic framework/graphene oxide composite fillers in mixed-matrix membranes for CO 2 separation

Materials Chemistry and Physics, 2018

Abstract Mixed-matrix membranes (MMMs) comprising of inorganic fillers dispersed in an organic ma... more Abstract Mixed-matrix membranes (MMMs) comprising of inorganic fillers dispersed in an organic matrix gather increased attention for separating gas mixtures due to potential for enhancement in separation selectivity, throughput, and material robustness. In the present study, ZIF-8 metal-organic framework (MOF) and ZIF-8/graphene oxide (GO) hybrid nanofillers were developed and incorporated into polysulfone (PSF) matrix. The fillers and the resulting MMMs were evaluated for their structural, morphological, and sorption characteristics, while the prepared membranes were tested for their permeation and selectivity properties for CO2, N2 and CH4. It is highlighted that, compared to the pristine PSF membrane, the PSF+(ZIF-8/GO) MMMs showed both enhanced CO2 permeability (up to an increase of 87%), and selectivity (up to an increase of 61% for the CO2/CH4 pair). In addition, the selectivity for the PSF+(ZIF-8/GO) MMM was increased by up to 7-fold compared to that of the PSF + ZIF-8 MMM. Based on the results reported, composite fillers combining the functionality of MOFs and GO have the potential to tune and boost the performance of polymeric membranes for CO2 separation from hydrocarbon gases, flue gas, and related gas mixtures.