【摘要】 应用平衡吸附法,研究外源玉米秸秆水溶性物质(WSS)对白浆土吸附Zn2+的影响,影响因素主要包括温度(298 K和318 K)、WSS浓度和接触时间(1～1 440 min)。结果表明:(1)不同温度条件影响下,白浆土对Zn2+的吸附热力学曲线主要包括起始的快速升高、中间的吸附平台和继续升高直至平衡3个阶段,经历电性吸附向配位吸附转变,最终促使二者共存。Langmuir方程能较好描述白浆土对Zn2+的吸附特征,升高温度有利于提高白浆土对Zn2+的最大缓冲容量,另外,白浆土对Zn2+的吸附是非自发、吸热且混乱度增加的过程。(2)玉米秸秆WSS的加入可有效抑制白浆土对Zn2+的吸附固定,减少两者的亲和力,降低白浆土对Zn2+的吸附强度,增大Zn2+在土壤溶液中的移动,有利于提高其植物有效性。(3)随玉米秸秆WSS浓度的增大,白浆土对Zn2+的吸附强度逐渐降低,可采用线性方程较好描述。(4)白浆土对Zn2+的动力学吸附主要包括短期快速吸附和长期慢速吸附两个阶段,第一阶段两个处理的吸附率分别达79.51%和96.80%。玉米秸秆WSS的加入可有效提高短期快速吸附阶段白浆土对Zn2+的吸附率,但同时WSS的加入却减少了白浆土对Zn2+的吸附固定。Elovich和双常数方程描述白浆土对Zn2+的吸附有较为明显的优势,WSS的添加扰乱了白浆土对Zn2+的动力学吸附过程。更多还原

【Abstract】 The equilibrium adsorption method was adopted to study the effect of water-soluble substances(WSS)from corn straw on the sorption of Zn(Ⅱ)on albic soil.The influencing factors of sorption included temperatures(298 K and 318 K),WSS concentrations and contact times(1~1 440 min).The results showed that:(1)Under the condition of different temperatures,the thermodynamic adsorption curves of Zn(Ⅱ)on albic soil included three stages,which contained the first rapid rising,middle platform and continued rising until getting to an equilibrium.The process experienced a transition from the electrical sorption to the complex sorption,ultimately,the above mentioned two types of sorptions were all existent.The adsorption characteristics were described well by Langmuir equation.The rising temperature would be helpful to improve the maximum buffer capacity of Zn(Ⅱ)on albic soil.In addition,the adsorption of Zn(Ⅱ)on albic soil was a process,which was non-spontaneous,endothermic and increased disorder degree.(2)Addition of WSS could inhibit the adsorbed process,reduce the affinity and adsorption intensity between Zn(Ⅱ)and tested soil,besides,it could increase the activity of Zn(Ⅱ)and improve its biological availability.(3)With the concentrations of WSS increasing,the adsorption intensity was decreased,whose process could be described by a linear equation.(4)The kinetic adsorption of Zn(Ⅱ)on the albic soil included two stages:short-term rapid sorption and long-term slow sorption.At the stage of short-term rapid adsorption,the adsorption rates from two treatments(no WSS and WSS)could get to 79.51% and 96.80% respectively,but at the same moment,addtion of WSS could reduce the adsorption intensity.The kinetic data could be better described by Elovich and dual-constant equation.The existence of WSS had disturbed the process of kinetic adsorption.更多还原