Abstract: Driven by sustainable-development strategies, photocatalysis has become a forefront approach for textile-dyeing wastewater remediation. ZnCdS possesses a well-matched conduction-band position, a narrow band gap and excellent chemical stability, making it a highly promising photocatalyst; however, it still suffers from severe photo-corrosion and ultrafast recombination of photogenerated carriers. Sodium alginate (SA) bears abundant -OH and -COOH groups that can build high-density adsorption sites for selective dye capture. After cross-linking modification, surface electrons are more readily excited, and an additional electron-buffer pool is created, which markedly suppresses ZnCdS electron-hole recombination and alleviates photo-corrosion, offering a new concept for constructing an efficient and stable "adsorption-photocatalysis" integrated system. Herein, ZnCdS/SA composite gel-beads were fabricated via a co-precipitation-cross-linking route. The removal of rhodamine B (RhB) was systematically evaluated under different light sources, and the effects of pH, irradiation time and cycle number on degradation efficiency were examined. Crystalline phase, morphology and functional-group evolution were analyzed by XRD, FTIR, etc. Under optimal conditions, RhB removal efficiency reached 98.77% while the gel-bead structure remained intact. The material exhibited the hexagonal ZnCdS phase with abundant surface protrusions and sufficient adsorption sites. Groups such as O-H, -COOH, COO-, and C-O-H captured RhB through electrostatic adsorption and redox synergy, while S, O, Fe and other elements participated in electron transfer. After five cycles, the degradation efficiency remained above 85%, confirming that ZnCdS/SA can efficiently and stably eliminate RhB from water via a dual "adsorption-photocatalysis" pathway, providing a feasible strategy for real textile wastewater treatment.

Key words: rhodamine B, chemical modification, cross-linking, adsorption, photocatalysis

摘要： 在可持续发展战略驱动下，光催化技术已成为印染废水治理的前沿方向。ZnCdS因导带位置匹配、带隙较窄且化学稳定性优异，被视为极具潜力的光催化材料，但仍受光腐蚀严重、光生载流子复合过快等瓶颈制约。海藻酸钠(SA)表面富含羟基与羧基官能团，可构筑高密度吸附位点，实现对染料分子的选择性捕集；通过交联改性，表面电子更易跃迁，形成额外电子缓冲池，从而显著抑制ZnCdS的光生空穴-电子复合，并缓解光腐蚀，为构建高效、稳定的“吸附-催化”一体化体系提供了新思路。基于此，本工作采用共沉淀-交联固化法制备ZnCdS/SA复合凝胶球，系统评价其在不同光源下对罗丹明B (RhB)的去除性能，并考察pH、光照时间及循环次数对降解效率的影响；同时借助X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)等手段对材料的晶相、形貌与官能团演变进行表征分析。结果表明，在最佳实验条件下，RhB去除率达98.77%，且凝胶球结构保持完整；材料呈ZnCdS六方晶相，表面褶皱丰富，吸附位点充足；O-H, -COOH, COO-, C-O-H等基团通过静电吸附与氧化还原协同作用捕获RhB, S, O, Fe等元素亦参与电子转移。经5次循环后，降解效率仍可保持85%以上，证实ZnCdS/SA可通过“吸附-光催化”双路径高效、稳定地去除水中的RhB，为实际印染废水处理提供了可行方案。

关键词: 罗丹明B, 化学改性, 交联, 吸附, 光催化