土壤或底泥对水体有机污染物的吸附是其重要的环境过程.选取了长三角代表性土壤进行了三苯甲烷类染料结晶紫(CV)的吸附实验,研究了初始pH、离子强度、天然有机质(NOM)、温度和搅动强度对土壤吸附结晶紫的影响.结果表明,随着pH增加,染料吸附量增加.离子强度对结晶紫吸附过程有一定的影响,而Ca2+的竞争较强,对CV吸附的影响较大.NOM和土壤对染料阳离子的竞争导致了吸附量的降低,可能是NOM与CV发生螯合或络合反应.结晶紫在土壤上吸附的假二级动力学模型的相关系数(R2=0.991)高于假一级动力学模型(R2=0.977).土壤对结晶紫的吸附更符合Langmuir等温线(R2=0.999).单层吸附容量qm为58.8mg·g-1(25℃),吸附过程单层吸附比多层吸附更加重要.热动力学参数ΔG0数值为负确定了吸附过程的自发性.
Crystal violet or gentian violet is a triarylmethane dye used as a dying stuff for paper,leather,etc.Due to its special bactericidal action,it is an important agency for aquatic pond cleaning and aquatic product antisepsis.Thus,crystal violet(CV)could enter the environment in various ways.However,it has been found that CV has the potential of carcinogenesis,teratogenesis and mutation,leading to vast attention to its aquaculture safety.Due to the fact that CV could easily contact with soil or deposit at aquafarm,it is important to recognize what will happen when CV is used to fishpond and touches to soil.In this work,the removal of crystal violet by the typical soil of the Yangtze River Delta was investigated from aqueous solution.The adsorption processes were studied according to the experiment parameters such as pH value,ion intensities,natural organic matters,temperature,and turbulence intensity.Both pH value and self-transformation process of crystal violet contributed to the decolorization process.The competition between the dye cations and Na+on the soil was marginal and it did not influence the adsorption process distinctly.However,Ca2+illustrated to have the competition with CV on the soil surface,which can obviously affect the adsorption process.The competition of dye cations between natural organic matters(NOMs)and the soil,as well as che-lation and complexation led to the decrease of adsorption capacities.Temperature did not play a decisive role when affecting adsorption behavior.The intensity of stirring affected the dispersion of dye cations in the aggregate solution,and the effective collisions between the dye cations and the soil binding sites.The kinetic data were better fitted by the pseudo-second-order kinetic model.The results of isotherms showed that the adsorption process may be combination of monolayer and multilayer adsorption.The negative values ofΔG0confirmed the feasibility of the process and spontaneous nature of adsorption.The negative value ofΔH0confirmed the exothermic p