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.

中文翻译：

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交联壳聚糖水凝胶上雷马唑亮蓝染料的截断：统计处理和实验评估

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，并增强其对 Remazol 亮蓝 R-19 染料的吸附能力。这是通过物理改性以获得水凝胶形式的材料和通过与巴比妥酸交联进行化学改性来实现的。使用各种分析技术（如 SEM-EDX、FT-IR、TGA-DTA、XRD 和 BET）对所得壳聚糖-巴比妥酸水凝胶 (CBH) 进行表征。使用 CBH 作为吸附剂来消除水介质中的 R-19 染料。利用响应面法 (RSM)，对参数进行微调，实现 R-19 染料去除率超过 95%。吸附行为严格遵循朗缪尔等温线和准二级动力学。一项有趣的观察表明，温度升高会导致 CBH 的吸附能力增加。根据 Langmuir 等温线模型，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-1、624.7 mg g-1、671.3 mg g-1 和 713.5 mg g-1。检查吸附过程的热力学揭示了其在整个温度范围内的自发性质（ΔG = -21.14 至 -27.09 kJ mol）。此外，使用克劳修斯-克拉佩龙方程对等量吸附热 (ΔH) 进行了评估，结果表明，由于表面负荷增加，随着温度从 301.15 K 升至 323.15 K，ΔH 从 1.85 kJ mol 增加到 2.16 kJ mol。这表明吸附的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，证明了该材料的重复利用能力。为合成过程计算的可持续性参数反映了 0.32 的显着较低的 E 因子值，表明该合成是环境友好的。