Department of Environmental Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 41566, Republic of Korea.
Department of Environmental Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 41566, Republic of Korea.
J Hazard Mater. 2020 Dec 5;400:123314. doi: 10.1016/j.jhazmat.2020.123314. Epub 2020 Jun 25.
An environment-friendly hydrogel was synthesized by entrapping Degussa P25 on the surface of a reduced graphene oxide (rGO)-polyacrylamide (PAM) matrix.The PAM content of the P25-rGO-PAM (PGP) hydrogel considerably influenced the adsorption and photocatalytic degradation of methylene blue (MB), and the optimal PAM content was 10% (w/v). Furthermore, rGO not only enhanced the adsorption capacity of the hydrogel by increasing the surface area but also increased the photodegradation efficiency synergistically by separating electron-hole pairs. The reaction kinetic constant for MB degradation by the hydrogel was 0.0276 min, which was three and five times the reaction kinetic constants of P25-PAM and rGO-PAM hydrogels, respectively. The synthesized PGP showed high stability and its MB degradation efficiency was considerably high up to five consecutive cycles under UV-irradiation. The eco-friendly nature of the hydrogel was evaluated on the basis of bacterial inactivation, and the treated water was found to be safe for use. Three key operating parameters (initial MB concentration, temperature, and pH) were optimized for maximizing MB removal using a response surface methodology. The complete MB removal efficiency was obtained for the optimal conditions of pH 9.4, a temperature of 31.2 °C, and an initial MB concentration of 5.2 mg/L.
一种环保水凝胶是通过将 Degussa P25 嵌入还原氧化石墨烯（rGO）-聚丙烯酰胺（PAM）基质的表面而合成的。P25-rGO-PAM（PGP）水凝胶中 PAM 的含量对亚甲基蓝（MB）的吸附和光催化降解有很大的影响，最佳的 PAM 含量为 10%（w/v）。此外，rGO 不仅通过增加表面积来提高水凝胶的吸附能力，而且通过分离电子-空穴对协同提高光降解效率。水凝胶对 MB 降解的反应动力学常数为 0.0276 min，分别是 P25-PAM 和 rGO-PAM 水凝胶反应动力学常数的 3 倍和 5 倍。合成的 PGP 表现出很高的稳定性，在紫外光照射下连续 5 次循环，其 MB 降解效率仍然很高。根据细菌失活评估了水凝胶的环保性质，发现处理后的水可安全使用。使用响应面法优化了三个关键操作参数（初始 MB 浓度、温度和 pH），以最大限度地去除 MB。在 pH 9.4、温度 31.2°C 和初始 MB 浓度 5.2 mg/L 的最佳条件下，可获得完全去除 MB 的效率。
