Conversion of Malaysian low-rank coal to mesoporous activated carbon:Structure characterization and adsorption properties  

作　　者：Ali H.Jawad Khudzir Ismail Mohd Azlan Mohd Ishak Lee D. Wilson 

机构地区：[1]Faculty of Applied Sciences,Universiti Teknologi MARA,40450 Shah Alam,Selangor,Malaysia [2]Faculty of Applied Sciences,Universiti Teknologi MARA,02600 Arau,Perlis,Malaysia [3]Department of Chemistry,University of Saskatchewan,Saskatoon,Saskatchewan S7N 5C9,Canada

出　　处：《Chinese Journal of Chemical Engineering》2019年第7期1716-1727,共12页中国化学工程学报（英文版）

摘　　要：Malaysian Selantik low-rank coal(SC)was used as a precursor to prepare a form of mesoporous activated carbon(SC-AC)with greater surface area(SA)via a microwave induced KOH-activation method.The characteristics of the SC and SC-AC were evaluated by the iodine number,ash content,bulk density,and moisture content The structure and surface characterization was carried out using pore structure analysis(BET),scanning electron microscopy with energy dispersive X-ray spectroscopy(SEM-EDX),X-ray diffraction(XRD),Fourier Transform Infrared(FTIR),elemental analysis(CHNS),thermogravimetric analysis(TGA),and determination of the point of zero charge(pH(PZC)).These results signify a mesoporous structure of SC-AC with an increase of ca.1160 times(BET SA=1094.3 m^2·g^-1)as compared with raw SC without activation(BET SA=1.23 m^2·g^-1).The adsorptive properties of the SC-AC with methylene blue(MB)was carried out at variable adsorbent dose(0.2-1.6 g·L^-1),solution pH(2-12),initial MB concentrations(25-400 mg·L^-1),and contact time(0-290 min)using batch mode operation.The kinetic profiles follow pseudo-second order kinetics and the equilibrium uptake of MB conforms to the Langmuir model with a maximum monolayer adsorption capacity of 491.7 mg g^-1 at 303 K.Thermodynamic functions revealed a spontaneous endothermic adsorption process.The mechanism of adsorption included mainly electrostatic attractions,hydrogen bonding interaction,andπ-πstacking interaction.This work shows that Malaysian Selantik low-rank coal is a promising precursor for the production of low-cost and efficient mesoporous activated carbon with substantive surface area.Malaysian Selantik low-rank coal（SC） was used as a precursor to prepare a form of mesoporous activated carbon（SC-AC） with greater surface area（SA） via a microwave induced KOH-activation method.The characteristics of the SC and SC-AC were evaluated by the iodine number,ash content,bulk density,and moisture content The structure and surface characterization was carried out using pore structure analysis（BET）,scanning electron microscopy with energy dispersive X-ray spectroscopy（SEM-EDX）,X-ray diffraction（XRD）,Fourier Transform Infrared（FTIR）,elemental analysis（CHNS）,thermogravimetric analysis（TGA）,and determination of the point of zero charge(pHPZC).These results signify a mesoporous structure of SC-AC with an increase of ca.1160 times(BET SA=1094.3 m2·g-1) as compared with raw SC without activation(BET SA=1.23 m2·g-1).The adsorptive properties of the SC-AC with methylene blue（MB） was carried out at variable adsorbent dose(0.2-1.6 g·L-1),solution pH（2-12）,initial MB concentrations(25-400 mg·L-1),and contact time（0-290 min） using batch mode operation.The kinetic profiles follow pseudo-second order kinetics and the equilibrium uptake of MB conforms to the Langmuir model with a maximum monolayer adsorption capacity of 491.7 mg g-1 at 303 K.Thermodynamic functions revealed a spontaneous endothermic adsorption process.The mechanism of adsorption included mainly electrostatic attractions,hydrogen bonding interaction,and π-π stacking interaction.This work shows that Malaysian Selantik low-rank coal is a promising precursor for the production of low-cost and efficient mesoporous activated carbon with substantive surface area.

关 键 词：Coal Activated carbon MESOPOROUS material KOH activation Microwave irradiation METHYLENE BLUE 

分 类 号：TQ[化学工程]