选取四环素作为代表抗生素,考察了溶液的pH值、离子强度(二价阳离子Ca2+和Mg2+)、腐殖酸3种环境因子对四环素在光催化剂二氧化钛(TiO2)上吸附的影响.结果表明,在3个不同pH(pH3、6和9)条件下的吸附等温线均符合Langmuir吸附等温方程,拟合的相关系数R2均大于0.999;四环素在TiO2上的吸附量在pH2—9范围内逐渐增大,在pH值高于9后显著减小.四环素在TiO2上的吸附量明显受到离子强度和腐殖酸的影响.本文对吸附机理及影响机制进行了讨论.
In this paper,the impact of three environmental factors including solution pH,ionic strength and humic acid on the adsorption of tetracycline to titanium dioxide(TiO2)photocatalyst was studied.The adsorption isotherms under different pH conditions(pH=3,6 and 9)were obtained,which fit the Langmuir equation well with R2 values all higher than 0.999.The adsorption of tetracycline to TiO2 increased with the increasing pH within the range of 2—9,whereas of decreased significantly when pH was higher than 9.The presence of divalent cations(Ca2+ and Mg2+)and humic acid also significantly inhibited the adsorption of tetracycline to TiO2.The mechanisms of absorption were discussed.