Tandem Efficient Bromine Removal and Silver Recovery by Resorcinol-Formaldehyde Resin Nanoparticles

Abstract

Halogen wastewater greatly threatens the health of human beings and aquatic organisms due to its severe toxicity, corrosiveness, and volatility. Efficient bromine removal is therefore urgently required, while existing Br2-capture materials often face challenges from limited water stability and possible halogen leaking. We report a facile and efficient aqueous Br2 removal method using submicron resorcinol-formaldehyde (RF) resin nanoparticles (NPs). The abundant aromatic groups dominate the Br2 removal by substitution reactions. An excellent Br2 conversion capacity of 7441 mg gRF –1 was achieved by RF NPs that outperform state-of-the-art materials by ∼2-fold, along with advantages including good water stability, low cost, and easy fabrication. Two recycling-coupled (electrochemical or H2O2-involved) Br2 removal routes further reveal the feasibility of in-depth halogen removal by RF NPs. The brominated resin can be downstream upcycled for silver recovery, realizing the harvesting of precious metal, reducing of heavy-metal pollution, and resource utilization of brominated resin.

Recovery of Ag(I) from Wastewater by Adsorption: Status and Challenges

“…After three regeneration cycles, when TSC−CC was added to an initial Ag(I) solution with a concentration of 320 mg/L and acidity of 0.5 mol/L, the removal efficiency remained at 73.6%, demonstrating significant potential for practical applications. Additionally, in the pursuit of versatile applications of chelating resins in wastewater, Wang et al [51] utilized submicron resorcinol−formaldehyde (RF) resin nanoparticles (NPs) to generate a brominated resin by combining them with bromine from halogen−containing wastewater, enabling cyclic recovery of silver in wastewater. Within 5 h, it exhibited a high capture capacity of 93.4 mg/g for the initial concentration of 100 ppm Ag(I).…”

Research Progress of Materials Used for Elemental Halogen Capture

“…2023 年, Wang 等 [37] 受芳香族化合物卤素亲电取代 反应的启发, 利用水稳定含芳香基团树脂聚合物材料进 行溴化取代反应使得溶液脱溴, 开发了使用亚微米间苯 二酚-甲醛(RF)树脂颗粒(NPs)去除水中 Br 2 的简便而有 效的方法, 所制备的胶体 RF NPs 在室温下, 具有高达 7441 mg•g RF − 1 的 Br 2 转化能力, 与 Br 2 捕获材料 PCN-605-H (4.2 g•g −1 的 Br 2 吸收能力)相比 [35] , RF NPs [37] 但也正是材料与 Br 2 之间的强化学反应导致了材料的不 可逆吸附, 因此在开发具有可逆吸附 Br 2 功能的材料时, 材料与 Br 2 分子之间反应的强弱是主要考虑因素之一. (2)与理论计算相结合.…”

“…随着新 型多孔材料的发展, 这些材料高的比表面积、可调的孔 隙率、多变的结构已被广泛应用于气体储存 [24] . 例如金 属有机框架材料(Metal-organic frameworks, MOFs) [25] 、 共价有机框架材料(Covalent organic frameworks, COFs) [26] 、多孔有机聚合物(Porous organic polymers, P O P s ) [ 2 7 ] 和 多 孔 有 机 笼 ( P o r o u s o rg a n i c c a g e s , POCs) [28][29] , 已经成功应用于 Cl 2 和 Br 2 吸附 [29][30][31][32][33][34][35][36][37] , 有关 I 2 吸附多孔材料的研究已较为成熟并正在深入开拓 中 [38][39] , 而有关 F 2 的吸附还未有相关研究. 除了多孔吸 附材料, 近年来有研究团队还报道了利用元素间的可逆 氧化还原反应, 实现金属卤化物钙钛矿(Metal Halide Perovskites, MHPs)和多卤晶体 XBr 3 (X＝Cs, (Et 4 N), (Bu 4 N))对 Cl 2 和 Br 2 的可逆固化和释放 [32][33][34] .…”

Selective Capture of Bromine over Iodine by a Nanometer-Sized Covalent Organic Framework Containing Imines and Hydrazones

“…16,18 However, only one resin has been reported in the literature for bromine removal in aqueous media, but with slow kinetics (>5 h). 19 These limitations hinder their practical application for halogen removal in aqueous media. In addition, they are prone to unwanted Br 2 leakage at elevated temperatures or when exposed to the ambient atmosphere, posing significant safety risks.…”

“…Such bromine capture materials may be broadly categorized into two sets on the basis of the mechanism involved, namely, (a) the physical/chemical adsorption and (b) the reversible chemical fixation. Advanced porous materials such as metal–organic frameworks (MOFs) or porous organic polymers (POPs) show superior adsorption performance toward the removal of bromine. − It is worth noting that these Br 2 removal methods are typically carried out in non-aqueous environments due to the poor water stability of active materials such as MOFs and perovskites. , However, only one resin has been reported in the literature for bromine removal in aqueous media, but with slow kinetics (>5 h) . These limitations hinder their practical application for halogen removal in aqueous media.…”