改性硅酸钙(CSH)对重金属废水中Ni^(2+)的吸附特性研究  

On the adsorptive behaviors of calcium silicate hydrate(CSH) to Ni^(2+)

作　　者：赵越[1] 郑欣 徐畅[3] 严群[1] 

机构地区：[1]江南大学环境与土木工程学院,江苏无锡214122 [2]武汉大学资源与环境科学学院,武汉430072 [3]靖江市环境监测站,江苏泰州224500

出　　处：《安全与环境学报》2017年第5期1904-1908,共5页Journal of Safety and Environment

基　　金：国家自然科学基金项目(51508230);江苏省产学研前瞻性联合研究项目(BY2016022-02);科技部水体污染控制与治理科技重大项目(2011ZX07301-002)

摘　　要：以硅灰石和氧化钙为原料制备改性硅酸钙(CSH),为了探讨改性硅酸钙对Ni^(2+)的吸附特性和机理,考察了初始p H值、吸附剂投加量、初始Ni^(2+)质量浓度和硅酸钙使用次数等因素对模拟废水中Ni^(2+)去除率的影响。结果表明,p H值在3.0~6.0、吸附剂投加量为1g/L、含Ni^(2+)废水质量浓度小于200 mg/L、硅酸钙前两次使用时,CSH对Ni^(2+)均有较高的去除效果。采用Langmuir等温吸附模型拟合CSH对Ni^(2+)的吸附,得到CSH对Ni^(2+)的最大吸附量为417 mg/g。结合吸附前后的扫描电镜-能谱(SEM-EDS)和X射线衍射(XRD)图谱分析,推测出CSH的主要结构为Ca Si2O5,CSH对Ni^(2+)的吸附主要发生在CSH表面并且是通过离子交换作用进行的。通过对CSH吸附去除Ni^(2+)过程中溶液离子浓度变化的研究推断出97%的Ni^(2+)通过离子交换作用被去除,剩余的Ni^(2+)通过表面络合作用去除。The given paper is aimed at introducing a sort of novel absorptive calcium silicate hydrate（ CSH） prepared from the wollastonite and calcium oxide to remove Ni2＋from the sewage with heavy metal contaminants. For the said purpose,we have first of all conducted an experiment and investigation of the effects of the original p H value,the dosage of the adsorbent,the original Ni2＋concentration and the number of times of CSH on the nickel removal,in hoping to identify and determine the optimal conditions for the Ni2＋removal. At the same time,we have also adopted the adsorption model of Langmuir so as to find the maximal CSH adsorption capacities for Ni2＋and characterize the mechanism of the adsorption process via the SEM-EDS,XRD spectrum and the changing rate of the ion concentration in the adsorptive process.The results of the aforementioned experiments have enabled us to find that the p H value is the main influential factor on the nickel adsorption. For example,the removal efficiency of CSH can all be made higher when the p H value can be made stay within a range between 3. 0-6. 0. In addition,the removal rate of Ni2＋can be made to reach 99% on the condition when the adopted CSH dosage is 1 g/L and the Ni2＋concentration is lower than 200 mg/L,if the CSH is adopted for the first twice. It is also necessary to notice that, when the adsorption capacities of CSH to Ni2＋reached its utmost limit of 417 mg/g,it would be possible to use Langmuir isotherm adsorption model with its related coefficient being 0. 999 3. On the other hand,based on the characterization of SEM-EDS and XRD spectrum,it can be found that the adsorption reaction that took place in the surface since the morphological status-in-situ of the CSH might have changed a great deal through the adsorption of Ni2＋. Besides,the original CSH powder might also get loosened in the process in which it turned into green and generate a lot of spherical granules on the CSH surface. Furthermore,it is also of great significance that the adsorption mecha

关 键 词：环境工程学 重金属废水 改性硅酸钙 吸附 镍 离子交换 

分 类 号：X703[环境科学与工程—环境工程]