Department of Industrial Chemistry, Mangalore University, Mangalagangothri, Karnataka 574199, India.
Department of Studies in Chemistry, Mangalore University, Mangalagangothri, Karnataka 574199, India; School of Applied Sciences, K. K. University, Biharsharif, Berauti, Bihar 803115, India.
Int J Biol Macromol. 2024 Oct;277(Pt 3):134454. doi: 10.1016/j.ijbiomac.2024.134454. Epub 2024 Aug 3.
A new guar gum hydrogel beads were fabricated by dropping method from an aqueous solution of guar gum (GG) using ammonium persulphate and polyethylene glycol as initiator and crosslinker respectively, for the adsorption of chlorpyrifos (CP) from water. The semi-crystalline nature of the synthesized beads was confirmed by FESEM analysis. The TGA studies implied that the beads were thermally stable up to 600 °C. The maximum swelling ratio of 1400 gg was attained at pH 9.2 and 80 min. The evidence of a strong absorption band was found in FTIR spectrum at 584 cm due to -P=S of the adsorbed pesticide CP. The maximum adsorption of CP was found to be 220.97 mgg. The adsorption followed pseudo second-order kinetics and Langmuir adsorption isotherm with regression coefficients 0.9998 and 0.9938 which followed the chemisorption process. It is due to the hydrolysis of CP at pH 9.2 to yield 3,5,6-trichloropyridinol which in turn reacts with the carboxylic group present in GG giving -N-C=O linkage. A -ΔG indicates that the process is spontaneous and involves chemisorption which is thermodynamically and kinetically favorable and a -ΔH value (-10.37 kJ/mol) suggests that the adsorption is exothermic.
采用滴加法，由水溶液中的瓜尔胶（GG）分别使用过硫酸铵和聚乙二醇作为引发剂和交联剂制备了一种新型瓜尔胶水凝胶珠，用于从水中吸附毒死蜱（CP）。FESEM 分析证实了合成珠的半结晶性质。TGA 研究表明，珠在 600°C 以下热稳定。在 pH 9.2 和 80 分钟时达到最大溶胀比 1400 gg。在 FTIR 光谱中发现了一个强吸收带的证据，在 584 cm 处归因于吸附农药 CP 的-P=S。发现 CP 的最大吸附量为 220.97 mgg。吸附遵循拟二级动力学和 Langmuir 吸附等温线，回归系数分别为 0.9998 和 0.9938，遵循化学吸附过程。这是由于 CP 在 pH 9.2 下水解生成 3,5,6-三氯吡啶醇，它反过来与 GG 中存在的羧酸基团反应生成-N-C=O 键。-ΔG 表明该过程是自发的，涉及化学吸附，这在热力学和动力学上都是有利的，-ΔH 值（-10.37 kJ/mol）表明吸附是放热的。
