使用Ti-XAD7纳米复合材料对影响水溶液中六价铬吸附的参数进行建模和优化：响应曲面法-中心复合设计方法、动力学及等温线研究
Modeling and optimizing parameters affecting hexavalent chromium adsorption from aqueous solutions using Ti-XAD7 nanocomposite: RSM-CCD approach, kinetic, and isotherm studies.
作者信息
Sharifi Sahar, Nabizadeh Ramin, Akbarpour Bahman, Azari Ali, Ghaffari Hamid Reza, Nazmara Shahrokh, Mahmoudi Babak, Shiri Leila, Yousefi Mahmood
机构信息
1Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
2Center for Air Quality Research, Institute for Environmental Research (IER), Tehran University of Medical Sciences, Tehran, Iran.
出版信息
J Environ Health Sci Eng. 2019 Dec 11;17(2):873-888. doi: 10.1007/s40201-019-00405-7. eCollection 2019 Dec.
BACKGROUND
Due to the high toxicity of chromium, particularly as Hexavalent chromium Cr (VI), it is removed from industrial effluents before their discharge into the environment by a variety of methods, including loading catalysts onto the polymeric supports. This study focused on the removal of Cr(VI) from aqueous solutions using Amberlite XAD7 resin loaded titanium dioxide (Ti-XAD7).
METHODS
Ti-XAD7 was synthesized using Amberlite XAD-7 impregnated with titanium tetraethoxide. The prepared Ti-XAD7 was characterized by using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Isotherms and kinetic studies were carried out to describe the adsorption behavior of adsorbent for the removal of Cr(VI) ions. Quadratic models considering independent variables, i.e. the initial Cr(VI) concentration, adsorbent dosage, time, and pH, were evaluated and optimized to describe the behavior of Cr(VI) adsorption onto the Ti-XAD7 using RSM based on a Five-level-four-factor CCD approach.
RESULTS
The accuracy and the fitting of the model were evaluated by ANOVA with R > 0.725 and value = 5.221 × 10. The optimum conditions for the adsorption process were an initial Cr(VI) concentration 2750 ppb, contact time of 51.53 min, pH of 8.7, and Ti-XAD7 dosage of 5.05 g/L. The results revealed that the Langmuir and Sips isotherm models with R = 0.998 and 0.999 were the The adsorption capacity of Ti-XAD7 and R constant were 2.73 mg/g and 0.063-0.076 based on the Langmuir isotherm, respectively. Kinetic studies also indicated that the adsorption behavior of Cr(VI) was acceptably explained by the Elovich kinetic model with a good fitting (R = 0.97).
CONCLUSIONS
Comparison of the Ti-XAD7 and XAD7 yield in chromium adsorption showed that modified XAD7 had higher removal efficiency (about 98%) compared to XAD7 alone.
背景
由于铬的高毒性，特别是六价铬Cr(VI)，在工业废水排放到环境之前，需要通过多种方法将其从废水中去除，包括将催化剂负载到聚合物载体上。本研究重点关注使用负载二氧化钛的Amberlite XAD7树脂（Ti-XAD7）从水溶液中去除Cr(VI)。
方法
用浸渍四乙氧基钛的Amberlite XAD-7合成Ti-XAD7。通过傅里叶变换红外光谱（FTIR）、扫描电子显微镜（SEM）和X射线衍射（XRD）对制备的Ti-XAD7进行表征。进行等温线和动力学研究以描述吸附剂对Cr(VI)离子的吸附行为。评估并优化了考虑自变量（即初始Cr(VI)浓度、吸附剂用量、时间和pH值）的二次模型，以使用基于五级四因素中心复合设计（CCD）方法的响应曲面法（RSM）来描述Cr(VI)在Ti-XAD7上的吸附行为。
结果
通过方差分析（ANOVA）评估模型的准确性和拟合度，R > 0.725且F值 = 5.221×10。吸附过程的最佳条件为初始Cr(VI)浓度2750 ppb、接触时间51.53分钟、pH值8.7以及Ti-XAD7用量5.05 g/L。结果表明，R值分别为0.998和0.999的朗缪尔等温线模型和西普斯等温线模型是最合适的。基于朗缪尔等温线，Ti-XAD7的吸附容量和R常数分别为2.73 mg/g和0.063 - 0.076。动力学研究还表明，Elovich动力学模型能够较好地解释Cr(VI)的吸附行为，拟合良好（R = 0.97）。
结论
Ti-XAD7和XAD7对铬吸附量的比较表明，改性后的XAD7比单独的XAD7具有更高的去除效率（约98%）。
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