以玉米芯为原料制备玉米芯生物炭(CCBC),探讨其对水中对硝基苯酚(PNP)的吸附特性,同时运用扫描电镜、傅里叶红外光谱、比表面积仪和元素分析对生物炭的理化性质进行表征,考察了溶液pH值和生物炭投加量对CCBC吸附PNP的影响.结果表明,在溶液pH值在2.0-11.0范围内,随着溶液pH值的升高,CCBC对PNP的吸附量持续减小,最佳溶液pH值应在2.0-7.0范围内.CCBC对PNP的吸附在4h时达到平衡,Elovich模型可以很好地拟合动力学数据,且颗粒内扩散不是唯一的控速步骤.吸附等温线符合Sips模型(R2＞0.98),最大吸附量为64.11 mg·g-1.热力学结果表明,CCBC对PNP的吸附是一个自发的吸热过程.PNP在CCBC上的吸附机制包括分配作用和表面吸附作用,且以表面吸附作用为主.
Removal of p-nitrophenol (PNP) from aqueous solution using corncob-derived biochar (CCBC) as an adsorbent was investigated.CCBC was characterized by SEM,FTIR,BET surface area and elemental analysis.The effects of solution pH,and adsorbent dosage on the adsorption performance of CCBC to PNP,and the adsorption kinetics,adsorption isotherms and adsorption thermodynamics were investigated.The adsorption capacity of PNP decreased with an increase of solution pH from 2.0 to 11.0,and the optimal pH value range was from 2.0 to 7.0.The adsorption of PNP onto CCBC reached equilibrium within 4 h.The kinetic data were well fitted by the Elovich model,and the intra-particle diffusion was not the sole rate-limiting step.The maximum adsorption capacity of CCBC for PNP was 64.11 mg·g-1.The Sips isotherm (R2＞0.98) was the best one to describe the adsorption behavior.The thermodynamic analysis indicated that the adsorption processes of PNP onto CCBC was spontaneous and endothermic.The sorption mechanism of CCBC was a combination of surface adsorption and partition,and dominated by surface adsorption.
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