Department of Chemistry, R.T.M. Nagpur University, Nagpur, 440033, India.
Department of Chemistry, R.T.M. Nagpur University, Nagpur, 440033, India.
Environ Res. 2024 Jul 1;252(Pt 1):118764. doi: 10.1016/j.envres.2024.118764. Epub 2024 Mar 26.
The primary aim of this research is to comprehensively assess the applicability of chitosan biopolymer towards water treatment application and to enhance its adsorption capacity towards Remazol brilliant blue R-19 dye. This has been achieved through physical modification to obtain the material in hydrogel form and chemical modification by crosslinking it with barbituric acid. The characterization of the resulting Chitosan-barbituric acid hydrogel (CBH) was carried out using various analytical techniques such as SEM-EDX, FT-IR, TGA-DTA, XRD, and BET. CBH was employed as the adsorbent to eliminate R-19 dye from aqueous media. Utilizing response surface methodology (RSM), the parameters were fine-tuned, leading to the achievement of more than a 95% removal for R-19 dye. The adsorption behavior closely adhered to the Langmuir isotherm and pseudo-second-order kinetics. An interesting observation indicated that the rise in temperature leads to rise in adsorption capacity of CBH. The maximum adsorption capacities evaluated at 301.15 K, 313.15 K, 318.15 K, and 323.15 K were 566.6 mg g, 624.7 mg g, 671.3 mg g, and 713.5 mg g respectively, in accordance with the Langmuir isotherm model. Examining the thermodynamics of the adsorption process revealed its spontaneous nature (ΔG = -21.14 to -27.09 kJ mol) across the entire temperature range. Furthermore, the assessment of the isosteric heat of adsorption (ΔH) was conducted using the Clausius-Clapeyron equation, with results indicating an increase in ΔH from 1.85 to 2.16 kJ mol with temperature rise from 301.15 K to 323.15 K due to augmented surface loading. This suggested the existence of lateral interactions between the adsorbed dye molecules. The potential of adsorbent for regeneration was investigated, demonstrating the ability to reuse the material. Sustainability parameter calculated for synthesis process reflected a notably low E-factor value of 0.32 demonstrated the synthesis is environment friendly.
本研究的主要目的是全面评估壳聚糖生物聚合物在水处理应用中的适用性，并提高其对雷马唑尔亮蓝 R-19 染料的吸附能力。这是通过物理改性获得水凝胶形式的材料和化学改性通过与巴比妥酸交联来实现的。所得壳聚糖-巴比妥酸水凝胶 (CBH) 的特性使用各种分析技术进行了表征，例如 SEM-EDX、FT-IR、TGA-DTA、XRD 和 BET。CBH 被用作吸附剂从水介质中去除 R-19 染料。利用响应面法 (RSM)，对参数进行了微调，导致 R-19 染料的去除率超过 95%。吸附行为紧密遵循朗缪尔等温线和伪二阶动力学。一个有趣的观察表明，温度升高会导致 CBH 的吸附容量增加。在 301.15 K、313.15 K、318.15 K 和 323.15 K 下评估的最大吸附容量分别为 566.6 mg g、624.7 mg g、671.3 mg g 和 713.5 mg g，符合朗缪尔等温线模型。研究吸附过程的热力学表明，整个温度范围内的吸附过程是自发的（ΔG=-21.14 至-27.09 kJ mol）。此外，使用克劳修斯-克拉佩龙方程评估了等吸附热 (ΔH)，结果表明，随着温度从 301.15 K 升高到 323.15 K，由于表面负载增加，ΔH 从 1.85 kJ mol 增加到 2.16 kJ mol。这表明吸附染料分子之间存在横向相互作用。研究了吸附剂的再生潜力，证明了材料的可重复使用性。合成过程的可持续性参数计算反映了非常低的 E 因子值 0.32，表明该合成具有环境友好性。
