Analysis of its adsorption mechanism
The global rise in the consumption of antimony (Sb) and related compounds can be attributed to increased pollution of water bodies. Antimony, a highly toxic and carcinogenic substance, exists in several oxidation states, namely: -III, 0, III, and V. However, III and V are the commonly available organic species, with the former exhibiting up to 10 times greater toxicity level than the latter. With the prevailing campaigns and increased awareness of the health effects of consuming toxic water, the highest acceptable levels of antimony in drinking water have been regulated by different authorities globally. These requirements, together with the increasing industrial applications of antimony and its compounds, several Sb removal techniques such as adsorption, solvent extraction, and precipitation, have been developed. Adsorption has, however, emerged as a sustainable, cost-effective, and potential approach despite being the least explored.
Despite having excellent porosity, surface area, tenability, and eco-friendly properties, the application of Co3O4 and its compounds in pollutant adsorbents have remained limited. Previous studies have revealed that the production of task-specific nanomaterials requires the construction of specific structures such as core-shell structures. This, however, requires suitable reaction conditions to ensure maximum tunability. Equipped with this knowledge, a team of researchers at Nanchang Hangkong University: Professor Hualin Jiang, Lei Tian (Master Student), Dr. Pinghua Chen, Dr. Yingchen Bai, Xueqin Li (Master Student), Professor Hongying Shu, and Professor Xubiao Luo assessed the feasibility of core-shell nanocomposite of Co3O4@rGO, prepared by template free self-assembled approach, as effective antimony adsorbent. Their work is currently published in the research journal, Environmental Research.
In their approach, the research team first analyzed the morphology and formation mechanisms of Co3O4@rGO of core-shell nanocomposite with respect to its time-dependent characteristics. This was done using the recorded processes of incubation, maturation, and collapse. Finally, the application potential of the Co3O4@rGO was validated by evaluating its adsorption performance towards high toxic antimony ions from natural water bodies.
The authors reported that Co3O4@rGO exhibited high performance in terms of adsorption capacity, anti-interference ability, and application pH range. Maximum adsorption capacities of 151.04 and 165.51 mg/g were recorded for Sb(III) and Sb(V), respectively. Moreover, the pH range was approximately 2 – 10. To this end, the prepared Co3O4@rGO nanocomposite can effectively and efficiently remove antimony and its compounds found in drinking water to the levels recommended by various regulatory authorities.
In summary, the study presented a comprehensive approach for the preparation of self-assembled core-shell nanocomposite of Co3O4@rGO and its potential application as efficient antimony adsorbent. Results showed that mesoporous Co3O4@rGO is an excellent adsorbent for antimony removal and can meet the required antimony levels in drinking water. Furthermore, the formation mechanism presented could be applied to prepare other core-shell nanocomposites. In a statement to Advances in Engineering, Professor Hualin Jiang said that their findings would accelerate the development of Co3O4@rGO based antimony adsorbents, which would also increase the industrial application of antimony and its compounds.
Jiang, H., Tian, L., Chen, P., Bai, Y., Li, X., Shu, H., & Luo, X. (2020). Efficient antimony removal by self-assembled core-shell nanocomposite of Co3O4@rGO and the analysis of its adsorption mechanism. Environmental Research, 187, 109657.