Department of Applied Chemistry and Chemical Engineering, University of Rajshahi, Rajshahi, 6205, Bangladesh.
Environ Sci Pollut Res Int. 2024 Oct;31(50):60401-60425. doi: 10.1007/s11356-024-35176-8. Epub 2024 Oct 9.
In this study, Zn-Al-SO LDH-functionalized biochar was fabricated using the co-precipitation method. The biochar was synthesized from waste cow dung using a low-temperature pyrolysis process (300 °C). The materials were fully characterized by TGA, FTIR, EDS, SEM, and XRD analysis. Then, a comparative study was performed to investigate the adsorption capacity of the materials against an anionic dye (i.e., methyl orange (MO)). The LDH-functionalized biochar demonstrated high adsorption capacity (400 mg/g in 120 min, at pH 5) compared to the raw biochar (212 mg/g in 120 min, at pH 5). The effect of various adsorption parameters (e.g., pH of the dye solution, temperature, initial concentration, adsorbent dosage, and contact time) was investigated. The adsorption of MO on LDH-functionalized biochar followed the Freundlich isotherm and pseudo-second-order kinetics, while the raw biochar followed the Langmuir isotherm and pseudo-second-order kinetics. The thermodynamic data indicated the endothermic nature of adsorption and an increase in the degree of randomness during adsorption. The enhanced adsorption capacity of the Zn-Al LDH-functionalized char was attributed to the synergistic effect of the surface adsorption into the porous biochar matrix, interlayer adsorption, and ion exchange capacity of the LDHs. Therefore, modification of waste cow dung-derived biochar with Zn-Al LDH can be a promising approach to fabricate a highly efficient adsorbent for toxic dyes from wastewater.
在这项研究中，采用共沉淀法制备了 Zn-Al-SO LDH 功能化生物炭。生物炭是使用低温热解工艺（300°C）从废牛粪中合成的。通过 TGA、FTIR、EDS、SEM 和 XRD 分析对材料进行了全面表征。然后，进行了对比研究，以研究材料对阴离子染料（即甲基橙（MO））的吸附能力。与原始生物炭（在 pH 5 下 120 分钟内 212 mg/g）相比，LDH 功能化生物炭具有更高的吸附能力（在 pH 5 下 120 分钟内 400 mg/g）。研究了各种吸附参数（例如，染料溶液的 pH、温度、初始浓度、吸附剂用量和接触时间）的影响。MO 在 LDH 功能化生物炭上的吸附遵循 Freundlich 等温线和拟二级动力学，而原始生物炭遵循 Langmuir 等温线和拟二级动力学。热力学数据表明吸附是吸热的，并且吸附过程中无序度增加。Zn-Al LDH 功能化炭的吸附能力增强归因于表面吸附到多孔生物炭基质中、层间吸附和 LDH 的离子交换能力的协同作用。因此，用 Zn-Al LDH 修饰废牛粪衍生的生物炭是一种很有前途的方法，可以制备用于从废水中去除有毒染料的高效吸附剂。
