为去除锑矿山废水中Sb(Ⅲ)污染,采用静态吸附试验,调查了湖泊水华主要藻种——微囊藻(Microcystis)对Sb(Ⅲ)的生物吸附特征及机理,并推断其反应方程式.结果表明:微囊藻吸附剂对Sb(Ⅲ)的吸附作用受生物量、pH、离子强度和吸附时间影响.最佳微囊藻吸附剂投加量为0.50 g,pH为4.0,吸附时间为60 min,室温条件,此时Sb(Ⅲ)的吸附量最大,为5.67 mg/g;微囊藻吸附剂对Sb(Ⅲ)的吸附速率非常快,遵循假二级动力学模型;pH对Sb(Ⅲ)吸附的影响与Sb形态以及吸附剂表面官能团质子化作用密切相关.阳离子(Na+和Ca2+)对Sb(Ⅲ)生物吸附效率的抑制作用随离子强度增加而加强,阴离子(NO3^-、Cl^-和SO4^(2-))未对其吸附产生影响.研究显示,微囊藻吸附剂对Sb(Ⅲ)的生物吸附以化学吸附为主.羧基和羟基为主要吸附位点,通过表面络合作用与Sb(OH)3相结合形成内源络合物.
To remove Sb( Ⅲ) pollution from Sb-mining effluents,the biosorption characteristics of Sb( Ⅲ) by dried biomass of dominate species of algae blooms,Microcystis,were investigated based on static adsorption experiments. The possible mechanisms and reaction equations between Sb( Ⅲ) and functional groups were speculated. The present results indicate that biosorbent dosages,pH values,ionic strength and contact time have significant effects on Sb( Ⅲ) biosorption efficiency. The maximal biosorption capacity was determined to be5. 67 mg/g at biosorption doses 0. 50 g,pH 4. 0,time 60 min and room temperature. The Sb( Ⅲ) biosorption kinetics obeyed the pseudosecond-order rate kinetics equation. The effects of pH values on the biosorption largely depended on the speciation of Sb and protonation of functional groups on the cell surface of the biosorbent. There were increasingly inhibitive effects of ionic strength of cations( e. g.,Na^+and Ca^(2+)) on the biosorption capacities,while the influences of anions( e. g.,NO3^-,Cl^-and SO4^(2-)) on the biosorption were insignificant. Chemical adsorption was the main driving mechanism for the biosorption. The protonated carboxyl and hydroxyl groups on the cell surface of Microcystis were involved in the Sb( OH)3biosorption through surface complexation to form inner complex.