Praipipat Pornsawai, Ngamsurach Pimploy, Khamenthong Yada, Himlee Niraya
Department of Environmental Science, Faculty of Science, Khon Kaen University, Khon Kaen, 40002, Thailand.
Environmental Applications of Recycled and Natural Materials (EARN) Laboratory, Khon Kaen University, Khon Kaen, 40002, Thailand.
Sci Rep. 2024 Oct 15;14(1):24082. doi: 10.1038/s41598-024-74634-8.
Wastewater contaminated with cadmium is a concern because of its toxicity, persistence, and bioaccumulation to the environment, ecosystem, and human health, so it is required to remove cadmium(II) ions before releasing them to receiving water. Banana powder beads (BPB), banana powder doped ZnO beads (BPZB), banana powder doped MgO beads (BPMB), and banana powder doped ZnO + MgO beads (BPZMB) were synthesized as the novel cadmium adsorbents, and their characterizations, cadmium adsorption performances, cadmium adsorption patterns and mechanisms, thermodynamic study, and reusability were investigated. BPMB had the highest specific surface area of 16.60 m/g and the smallest pore size of 1.69 nm than other materials. BPB was an amorphous structure, whereas BPZB, BPMB, and BPZMB were crystalline structures presenting their specific metal oxide peaks of ZnO or MgO. They were coarse surfaces and had a spherical shape consisting of C, O, Ca, Cl, and Na. Their main functional groups were O-H, C-H, C=O, C-O, and N-H. The points of zero charge of BPB, BPZB, BPMB, and BPZMB were 5.37, 6.75, 9.87, and 9.43. The cadmium removal efficiencies of BPB, BPZB, BPMB, and BPZMB were 89.18%, 96.62%, 99.59%, and 97.85%, and their q values were 90.09, 232.56, 454.55, and 303.03 mg/g, respectively. Thus, the metal oxide helped to improve material efficiency, especially MgO. The Freundlich and pseudo-second-order kinetic models were good fit models for describing their adsorption patterns and mechanisms. The increasing temperature affected to decrease their cadmium adsorptions. They could be reused in more than 3 cycles of more than 73% of cadmium adsorption. The electrostatic interaction played an important role in describing their cadmium adsorptions. Therefore, BPBM was a good cadmium adsorbent for application in industrial wastewater treatment since it had a higher performance of cadmium adsorption than other materials.
受镉污染的废水令人担忧，因为它具有毒性、持久性，且会在环境、生态系统和人类健康中生物累积，所以在将镉（II）离子排放到受纳水体之前需要将其去除。合成了香蕉粉珠（BPB）、掺杂氧化锌的香蕉粉珠（BPZB）、掺杂氧化镁的香蕉粉珠（BPMB）和掺杂氧化锌+氧化镁的香蕉粉珠（BPZMB）作为新型镉吸附剂，并对它们的表征、镉吸附性能、镉吸附模式和机理、热力学研究以及可重复使用性进行了研究。BPMB具有最高的比表面积，为16.60 m/g，且孔径最小，为1.69 nm，优于其他材料。BPB为无定形结构，而BPZB、BPMB和BPZMB为晶体结构，呈现出氧化锌或氧化镁的特定金属氧化物峰。它们表面粗糙，呈球形，由碳、氧、钙、氯和钠组成。其主要官能团为O-H、C-H、C=O、C-O和N-H。BPB、BPZB、BPMB和BPZMB的零电荷点分别为5.37、6.75、9.87和9.43。BPB、BPZB、BPMB和BPZMB的镉去除效率分别为89.18%、96.62%、99.59%和97.85%，其q值分别为90.09、232.56、454.55和303.03 mg/g。因此，金属氧化物有助于提高材料效率，尤其是氧化镁。弗伦德利希和准二级动力学模型是描述其吸附模式和机理的良好拟合模型。温度升高会降低它们对镉的吸附。它们可以重复使用3个以上周期，镉吸附率超过73%。静电相互作用在描述它们对镉的吸附中起重要作用。因此，BPMB是一种用于工业废水处理的良好镉吸附剂，因为它比其他材料具有更高的镉吸附性能。
