Functionalization of whole biowaste to develop new value-added materials by applying clean synthetic protocols is emerging as an attractive research area for a sustainable environment. Herein, we report the synthesis and detailed characterization of pine needles-glycidyltrimethylammonium chloride (G-PNs), which was accomplished by incorporating quaternized ammonium groups on the surface of pine needles by a polymer analogous reaction. As-synthesized G-PNs were explored as an adsorbent for the selective removal of anionic dyes, namely Congo red (CR) and methyl orange (MO) from their solutions. Adsorption capacity, kinetics, and thermodynamic behaviour of G-PNs with the dyes as a function of time, temperature, pH, and dye concentration were also analyzed. Various kinetic and adsorption isotherm models were used to identify the mechanism of the CR and MO adsorption process. The adsorption studies revealed a significantly high efficiency and selectivity of the adsorbent for anionic dyes with %removal of 94.76% and 93.96% for CR and MO, respectively. The adsorption process followed pseudo-second-order kinetic and Langmuir isotherm models with a maximum adsorption capacity (q_m) of 251.8 mg/g and 263.1 mg/g for CR and MO, respectively. Furthermore, after fifteen adsorption-desorption cycles, the effectiveness of the adsorbent for the dyes remained appreciable. Additionally, dye adsorption studies of G-PNs were also carried out for dye removal from real textile effluent. The use of bio-waste-based G-PNs thus resulted in environmentally friendly, cost-effective, biodegradable, and green material that has good potential for use in real samples to remove anionic dyes from the textile wastewater treatment.

Graphical Abstract

中文翻译：

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缩水甘油基三甲基氯化铵改性整松针合成的高效绿色阴离子染料吸附剂：合成、动力学和热力学研究

通过应用清洁合成协议对整个生物废物进行功能化以开发新的增值材料正在成为可持续环境的一个有吸引力的研究领域。在此，我们报道了松针缩水甘油基三甲基氯化铵（G-PNs）的合成和详细表征，该产品是通过聚合物类似反应在松针表面引入季铵基团来实现的。合成的 G-PNs 被探索作为一种吸附剂，用于选择性去除溶液中的阴离子染料，即刚果红 (CR) 和甲基橙 (MO)。还分析了 G-PN 与染料的吸附能力、动力学和热力学行为随时间、温度、pH 和染料浓度的变化。使用各种动力学和吸附等温线模型来确定 CR 和 MO 吸附过程的机理。吸附研究表明，该吸附剂对阴离子染料具有极高的效率和选择性，CR 和 MO 的去除率分别为 94.76% 和 93.96%。吸附过程遵循准二级动力学和Langmuir等温线模型，具有最大吸附容量（q_{CR 和 MO 的m} ) 分别为 251.8 mg/g 和 263.1 mg/g。此外，经过十五次吸附-解吸循环后，吸附剂对染料的有效性仍然很明显。此外，还进行了 G-PN 的染料吸附研究，以去除真实纺织废水中的染料。因此，基于生物废物的 G-PNs 的使用产生了环境友好、具有成本效益、可生物降解的绿色材料，在实际样品中具有良好的潜力，可用于去除纺织废水处理中的阴离子染料。

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