Fabrication of superparamagnetic adsorbent based on layered double hydroxide as effective nanoadsorbent for removal of Sb (III) from water samples

Arsenic and antimony desorption in water treatment processes: Scaling up challenges with emerging adsorbents

The metalloids arsenic (As) and antimony (Sb) belong to the pnictogen group of the periodic table; they share many characteristics, including their toxic and carcinogenic properties; and rank as high-priority pollutants in the United States and the European Union. Adsorption is one of the most effective techniques for removing both elements and desorption, for further reuse, is a part of the process to make adsorption more sustainable and feasible. This review presents the current state of knowledge on arsenic and antimony desorption from exhausted adsorbents previously used in water treatment, that has been reported in the literature. The application of different types of eluents to desorb As and Sb and their desorption performance are described. The regeneration of saturated adsorbents and adsorbate recovery techniques are outlined, including the fate of spent media and possible alternatives for waste disposal of exhausted materials. Future research directions are discussed, as well as current issues including the lack of environmental impact analysis of emerging adsorbents.

Community ecological study on the reduction of soil antimony bioavailability by SRB-based remediation technologies

Sulfate-reducing bacteria (SRB) were effective in stabilizing Sb. However, the influence of electron donors and acceptors during SRB remediation, as well as the ecological principles involved, remained unclear. In this study, Desulfovibrio desulfuricans ATCC 7757 was utilized to stabilize soil Sb within microcosm. Humic acid (HA) or sodium sulfate (Na2SO4) were employed to enhance SRB capacity. The SRB+HA treatment exhibited the highest Sb stabilization rate, achieving 58.40%. Bacterial community analysis revealed that SRB altered soil bacterial diversity, community composition, and assembly processes, with homogeneous selection as the predominant assembly processes. When HA and Na2SO4 significantly modified the stimulated microbial community succession trajectories, shaped the taxonomic composition and interactions of the bacterial community, they showed converse effect in shaping bacterial community which were both helpful for promoting dissimilatory sulfate reduction. Na2SO4 facilitated SRB-mediated anaerobic reduction and promoted interactions between SRB and bacteria involved in nitrogen and sulfur cycling. The HA stimulated electron generation and storage, and enhanced the interactions between SRB and bacteria possessing heavy metal tolerance or carbohydrate degradation capabilities.

Biochar microtube interconnected hydrotalcite nanosheets for the adsorption of aqueous Sb(III)

Actuated by the non-ionic heavy metal of antimony (Sb) contaminants with undesired toxicity to the environment and human health, capturing Sb is urgent to remedy contaminated water. Herein, the lamellar MnCo hydrotalcite was grown on catkin-derived biochar through the in situ etching of ZIF-L to construct a hierarchical microtube@nanosheet hybrid (CLMH) for Sb immobilization. The adsorption behaviour and mechanism of trivalent antimony (Sb (III)) on the CLMH were investigated. The CLMH shows good pH applicability for capturing Sb(III) at pH from 2 to 9. The excellent adsorption capacity of CLMH for Sb(III) is 247.62 mg g^-1at 303 K, and the endothermic process is proved by the positive value of ΔH0(10.54 kJ mol^-1). The adsorption process is fitted with the intra-particle diffusion model, which can be described with external mass transfer, intraparticle diffusion in pores, and equilibrium stage. The adsorption mechanism is proved, which includes the bind of Metal-O-Sb bonds by inner-sphere complex, the embedding of Sb in the intercalation of hydrotalcite, redox between Mn and Sb, and functional groups dependent anchoring effect. The work benefits the understanding of the antimony removal behaviour over the hierarchical microtube@nanosheet hybrids.