Adsorption characteristics and Mechanism of Cd2+on biochar with different pyrolysis temperatures produced from eucalyptus leaves
GAO Li-yang1, DENG Jin-huan1, TANG Guo-qiang3, HUANG Xiang-neng1, CAI Kun-zheng1,2, CAI Yi-xia1,2, HUANG Fei1,2
1. College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China; 2. Key Laboratory of Tropical Agro-Environment, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China; 3. College of Agriculture, South China Agricultural University, Guangzhou 510642, China
Abstract：Three types of biochar were generated from eucalyptus leaves under different pyrolysis temperatures of 300,500and 700℃(referred as BC300,BC500 and BC700),and their surface characteristics and Cd (Ⅱ) adsorption processes were investigated using element analysis,BET-N2,Zeta analysis,Boehm titration,SEM-EDS,FTIR and other analytical methods.The results showed that as pyrolysis temperature increased,the yields decreased,but the ash content,pH,specific surface area and Zeta potential increased.The adsorptive capacity followed in the order of BC700(94.32mg/g),BC500(67.07mg/g) and BC300(60.38mg/g),and both Langmuir and Freundlich models were reasonable to describe the adsorption behavior of BC300and BC500,but Freundlich model was more suitable to describe the adsorption processes of BC700.Adsorption kinetic showed the equilibrium time followed by 540min (BC300),360min (BC500) and 80min (BC700),which were better fitted by pseudo-second order model (R2>0.98) indicating the adsorption was mainly chemical.The results of FTIR and Boehm titration indicated that the spectra of BC700incurred more changes than those of other biochars,which suggested more functional groups were involved in the adsorption including -OH、C=O、C=C、C-O groups.BC700biochar are more effective than other biochars to remove Cd2+,which was due to larger specific surface,more negative charge amount and functional groups.Based on the studies above,the removal of Cd2+ were mainly by surface electrostatic adsorption and chelation.
郜礼阳, 邓金环, 唐国强, 黄祥能, 蔡昆争, 蔡一霞, 黄飞. 不同温度桉树叶生物炭对Cd2+的吸附特性及机制[J]. 中国环境科学, 2018, 38(3): 1001-1009.
GAO Li-yang, DENG Jin-huan, TANG Guo-qiang, HUANG Xiang-neng, CAI Kun-zheng, CAI Yi-xia, HUANG Fei. Adsorption characteristics and Mechanism of Cd2+on biochar with different pyrolysis temperatures produced from eucalyptus leaves. CHINA ENVIRONMENTAL SCIENCECE, 2018, 38(3): 1001-1009.
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