BTCABs吸附剂对Ni(Ⅱ)的吸附

Adsorption of Ni(Ⅱ)on adsorbent of BTCABs

为了减少Ni(Ⅱ)对环境的危害,以海藻酸钙作为包埋基质,将生物炭和单宁进行包埋,成功制备出生物炭/单宁/海藻酸钙微球(BTCABs)。采用SEM,FT-IR和BET对BTCABs的表面形态和结构进行表征。考察溶液Ni(Ⅱ)初始浓度、温度和pH值对吸附的影响。BTCAB对Ni(Ⅱ)的最大吸附量为48.12 mg/g。生物炭的高比表面积与单宁的酚羟基对Ni(Ⅱ)吸附具有协同作用。吸附行为符合Langmuir与Freundlich模型,表明吸附存在多种吸附机理。BTCABs对Ni(Ⅱ)的吸附遵循准二级动力学模型,反映吸附过程受吸附剂表面膜扩散及颗粒内扩散共同控制。以5%CaCl_(2)水溶液作为脱附剂,在BTCABs重复再生第5次吸附时,吸附量仍可达到最大吸附量的73.8%。

In order to reduce the contamination of Ni(Ⅱ).Calcium alginate was used as the embedding matrix to embed biochar and tannin,the biochar/tannin/calcium alginate beads(BTCABs)were successfully prepared.The composite was analysed by the SEM,FT-IR,and BET patterns.The effects of initial Ni(Ⅱ)concentration,temperature and pH of solution on the adsorption of Ni(Ⅱ)by BTCABs were investigated.The maximum adsorption capacity of BTCAB for Ni(Ⅱ)was 48.12 mg/g,which is due to the synergistic effect of the high specific surface area of biochar and phenolic hydroxyl groups of tannin.The experimental data were well described by the models of Langmuir and Freundlich.This confirms the existence of multiple mechanisms in the adsorption process.The adsorption of Ni(Ⅱ)on BTCABs obeys pseudo-second-order kinetics equation,and the adsorption is controlled by both membrane diffusion of adsorbent surface and intraparticle diffusion.The aqueous solution with the concentration of 5%CaCl_(2) was used as desorption agent.After repeated regeneration,in the fifth adsorption the adsorption capacity of BTCABs could still reach about 73.8%of the maximum adsorption capacity.