摘要
以半焦(SC)为原料,采用KOH活化法对其进行活化,制备出中孔半焦活性炭(SAC)吸附剂去除水中苯酚.考察了初始浓度、接触时间、溶液pH、共存盐离子及有机物等条件对吸附性能的影响,并对吸附前后的SAC进行表征.实验结果表明:在25℃条件下,SAC对苯酚的吸附等温线符合Freundlich模型,最大吸附量为271.55 mg/g,吸附效果明显优于SC(39.34 mg/g);吸附动力学遵循拟二级动力学方程,在前50 min具有较快的吸附速率;苯酚初始浓度为250 mg/g时,动态吸附量为159.86 mg/g,苯酚出水浓度低于0.5 mg/L.SAC具有较强的抗干扰能力,对苯酚的有效吸附pH范围为3～9,且当溶液中存在高盐/有机物时,SAC对苯酚的吸附量稳定在165 mg/g.采用过硫酸钾氧化法对饱和半焦活性炭(ASAC)进行再生,当溶液pH为5,过硫酸钾(KPS)浓度为0.75 g/L,再生时间为4 h时,再生效果最优,SAC经三次循环再生后对苯酚的吸附量达到72 mg/g.吸附前后SAC表征结果表明:SAC去除苯酚主要是通过含氧官能团与苯酚之间产生的π-π相互作用力.活化后的中孔半焦活性炭对复杂水体中的苯酚具有很好的吸附效果,且可通过过硫酸盐氧化再生,其在含酚废水处理方面具有广阔的应用前景.
Abstract
Mesoporous semi-coke activated carbon(SAC)adsorbent was prepared for the removal of phenol from water using semi-coke(SC)as raw material and its activation by KOH activation method.The effects of conditions such as initial concentration,contact time,solution pH,co-existing salt ions and organic matter on the adsorption performance were investigated and the SAC before and after adsorption was characterised.The experimental results showed that the adsorption isotherm of phenol by SAC at 25 ℃ was in accordance with the Freundlich model,and the maximum adsorption amount was 271.55 mg/g,which was significantly better than that of SC(39.34 mg/g);the adsorption kinetics followed the proposed second-order kinetic equation,and the adsorption rate had a faster rate in the first 50 min;the dynamic adsorption was achieved at an initial concentration of phenol of 250 mg/g,the dynamic adsorption amount was 159.86 mg/g,and the phenol effluent concentration was lower than 0.5 mg/L.SAC had strong anti-interference ability,the effective adsorption of phenol in the pH range of 3～9,and the adsorption amount of phenol by SAC was stable at 165 mg/g when there were high salts/organic matter in the solution.potassium persulfate oxidation was used to regenerate the saturated semicoke activated carbon(ASAC)was regenerated when the solution pH was 5,the concentration of potassium persulfate(KPS)was 0.75 g/L,and the regeneration time was 4 h.The adsorption of phenol by SAC after three cycles of regeneration reached 72 mg/g.The results of the characterisation of SAC before and after adsorption showed that the removal of phenol by SAC was mainly through the π-π interaction force.The activated mesoporous semi-coke activated carbon has good adsorption effect on phenol in complex water and can be regenerated by persulfate oxidation,which has a broad application prospect in phenol wastewater treatment.
维普
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