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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。
The effects of WSS on the adsorption of Zn2 + on alluvial soil were studied by equilibrium adsorption. The main influencing factors include temperature (298 K and 318 K), WSS concentration and contact time (1 ~ 1440 min). The results show that: (1) The thermodynamic curves of Zn2 + adsorption on white soil include the initial rapid increase under different temperature conditions, the middle adsorption platform continues to rise up to equilibrium three stages, Bit adsorption changes, eventually prompted the two coexist. The Langmuir equation can better describe the adsorption characteristics of Zn2 + on white soil. Increasing the temperature is beneficial to increase the maximum buffer capacity of Zn2 + on white soil. In addition, adsorption of Zn2 + on white soil is non spontaneous, endothermic and chaotic increase. process. (2) Addition of corn stalk WSS can effectively inhibit the adsorption and fixation of Zn2 + in albic soil, reduce the affinity between the two, decrease the adsorption strength of Zn2 + on white soil and increase the movement of Zn2 + in soil solution, Plant Effectiveness. (3) With the increase of WSS concentration of corn stalks, the adsorption strength of Zn2 + in albic soil gradually decreased, which can be described by the linear equation. (4) Kinetic adsorption of Zn2 + by albic soil mainly includes short-term fast adsorption and long-term slow adsorption, the first two adsorption rates are 79.51% and 96.80% respectively. Addition of corn stalk WSS can effectively increase the adsorption rate of Zn2 + on white soil in the short-term rapid adsorption stage, but the addition of WSS reduced the adsorption and fixation of Zn2 + in white soil. Elovich and the biconear equation describe the obvious adsorption of Zn2 + on white soil, and the addition of WSS disturbed the kinetic adsorption of Zn2 + on white soil.