Abstract

Batch adsorption experiments were carried out for the removal of methylene blue (MB) cationic dye from its aqueous solution using rubber-based hydrogel. In this work, the adsorption of two rubber-based hydrogels, namely maleated liquid natural rubber/acrylic acid hydrogel (LNR-g-MaH/AAc) and maleated liquid natural rubber/acrylic acid/montmorillonite hydrogel (LNR-g-MaH/AAc/MMT), was optimised by response surface methodology (RSM) using a central composite rotatable design (CCRD). The effects of various parameters, such as adsorbent mass and initial concentrations of MB, were examined. The hydrogels were characterised using field emission scanning electron microscopy, thermogravimetric analysis (TGA), and fourier-transform infrared (FTIR). A total of 13 experiments were conducted to establish a quadratic model. Among those two rubber-based hydrogels, LNR-g-MaH/AAc/MMT hydrogel had higher optimum adsorption efficiency with 99.07% of dye removal percentage. The optimum dye performance of LNR-g-MaH/AAc hydrogel was also effective as the dye removal percentage was about 95.46%. Those responses were recorded when the adsorbent mass and initial concentration of MB were optimally set as 0.55 g, and 5.50 mg L⁻¹, respectively. The Freundlich isotherm model was found to be best fitted to adsorption for those two hydrogels. The maximum adsorption capacities were 1.85 mg/g for LNR-g-MaH/AAc and 9.74 mg/g for LNR-g-MaH/AAc. Two kinetic models were tested to correlate the experimental data and the sorption was discovered to fit well with the pseudo-second-order kinetic model. It was found that by introducing of montmorillonite (MMT) could improve the adsorption ability of the LNR-g-MaH/AAc hydrogel.

中文翻译：

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改善橡胶基水凝胶的吸附性能：通过响应面方法，等温线和动力学研究进行优化

摘要

使用橡胶基水凝胶进行了批量吸附实验，以从其水溶液中去除亚甲基蓝（MB）阳离子染料。在这项工作中，两种橡胶基水凝胶的吸附，即马来酸化的天然橡胶/丙烯酸水凝胶（LNR-g-MaH / AAc）和马来酸化的天然橡胶/丙烯酸/蒙脱石水凝胶（LNR-g-MaH / AAc） / MMT），通过响应面方法（RSM）使用中央复合材料可旋转设计（CCRD）进行了优化。检查了各种参数的影响，例如吸附剂质量和MB的初始浓度。使用场发射扫描电子显微镜，热重分析（TGA）和傅里叶变换红外（FTIR）对水凝胶进行表征。总共进行了13个实验以建立二次模型。在这两种橡胶基水凝胶中，LNR-g-MaH / AAc / MMT水凝胶具有更高的最佳吸附效率，染料去除率高达99.07％。LNR-g-MaH / AAc水凝胶的最佳染料性能也很有效，因为染料去除率约为95.46％。当MB的吸附剂质量和初始浓度最佳设置为0.55 g和5.50 mg L时记录这些响应^-1。发现Freundlich等温模型最适合这两种水凝胶的吸附。LNR-g-MaH / AAc的最大吸附容量为1.85 mg / g，LNR-g-MaH / AAc的最大吸附容量为9.74 mg / g。测试了两个动力学模型以关联实验数据，并发现吸附与拟二级动力学模型非常吻合。发现通过引入蒙脱土（MMT）可以提高LNR-g-MaH / AAc水凝胶的吸附能力。