The performance and mechanism of Cr(Ⅵ)adsorption by layered bimetallic oxide supported on activated carbon of olive pomace
Olive pomace was taken as raw material to prepare olive pomace activated carbon(OP-AC)by the alkaline high-temperature activation method,then FeAl-LDH@AC composite was prepared by loading OP-AC with layered double metal hydroxide(FEAL-LDH)by the chemical coprecipitation method.The results showed that the FeAl-LDH@AC composite with the best removal effect on Cr(Ⅵ)was prepared under the conditions of Fe-Al molar ratio of 2∶1,solid-liquid ratio of 1∶15 and coprecipitation time of 24 h.XRD and FT-IR spectra showed that FeAl-LDH@AC composites contained rich oxygen-containing functional groups,and a large number of Fe elements and Al elements attached on the surface of OP-AC,and the successful combination between Fe elements/Al element and OP-AC occurred.The pore structure in FeAl-LDH@AC composites was mainly micropores,and there were also a few mesopores and macropores.Under the conditions of pH=2,initial concentration of Cr(Ⅵ)20mg·L-1,adsorption time 24h and FeAl-LDH@AC dosage of 20 g·L-1,the removal efficiency of Cr(Ⅵ)by FeAl-LDH@AC composite reached 97.85％,and the adsorption capacity was 0.9785 mg·g-1.The adsorption process of Cr(Ⅵ)by FeAl-LDH@AC composite conformed to Freundlich model and quasi-second-order adsorption kinetics model,indicating that the adsorption process was inclined to chemical adsorption and multi-molecular layer adsorption on heterogeneous surfaces.Based on Weber-Morris particle diffusion equation model fitting results,the whole adsorption stage could be dominated by both membrane diffusion and internal diffusion.The above results could provide a reference for effectively removing Cr(Ⅵ)by FeAl-LDH@AC composite and resource utilization of olive pomace.
LDHsactivated carbonheavy metal ionscomposite materials
国家科技期刊平台
NSTL
万方数据
