Selective Adsorption and Recovery of Silver from Acidic Solution Using Biomass-Derived Sulfur-Doped Porous Carbon

Abstract

It is vital to recycle precious metals effectively such as silver from waste sources because of limited natural reserves. Herein, passion fruit (Passiflora edulis Sims) shell-derived S-doped porous carbons (SPCs) were newly synthesized by hydrothermal carbonization and following with activation by KOH/(NH 4 ) 2 SO 4 , and the adsorption of Ag + on SPC under acidic solutions was investigated. It was found that the activator of (NH 4 ) 2 SO 4 can not only introduce the doping of S elements but also increase the proportion of mesopores in the as-prepared SPC. As the active site, the increasing S doping can improve the adsorption of Ag + on SPC. The kinetic data of Ag + adsorption by SPC was consistent with the pseudosecond-order kinetic model. The Langmuir isothermal model was used to well fit the Ag + adsorption isotherms of SPC, and the maximum adsorption capacity of the optimized SPC-3 for Ag + is up to 115 mg/g in 0.5 mol/L HNO 3 solution. SPC-3 showed good selectivity toward Ag + over diverse competing cations, which is mainly attributed to the strong bonding between Ag + ions and the sulfur-containing functional groups on the surface of SPC-3 resulting in the formation of Ag 2 S nanoparticles. The adsorbed Ag could be recovered as an elemental form by a simple calcination. This study provides a new insight into the design of an environmentally friendly and efficient adsorbent for the selective recovery of silver from acidic aqueous media.

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

“…In addition to chitosan and cellulose, the abundant carbon content in biomass provides a solid foundation for the preparation of biochar materials, which have shown remarkable potential in the field of water treatment. For example, Fan et al [44] utilized discarded passion fruit peels as a precursor for biomass and synthesized sulfur−doped porous carbon materials (SPCs) through hydrothermal carbonization coupling. Experimental results demonstrated its excellent adsorption of Ag(I) in acidic aqueous solutions, with a maximum adsorption capacity of 115 mg/g.…”

Exploring the Potential of Biochar Derived from Chinese Herbal Medicine Residue for Efficient Removal of Norfloxacin

“…However, it is crucial to recognize that the adsorption efficiency is contingent upon the specific adsorbent type and its inherent characteristics [13][14][15]. To date, various adsorbents, including activated carbon [16], nanotube [17], metal-organic frameworks (MOFs) [18], osmotic membrane bioreactors [19], clay [20], and silica [21], have been extensively utilized for the removal of antibiotics. Specifically, biochar has attracted significant attention in the removal process of antibiotics owing to its easy availability, large surface area, abundance of surface functional groups, and developed pores [22,23].…”

ZIF-67 and Biomass-Derived N, S-Codoped Activated Carbon Composite Derivative for High-Effective Removal of Hydroquinone from Water

“…Generally, the specific surface area and functional groups of the adsorbent play a crucial role in the adsorption performance of HQ. Doping N and S atoms in activated carbon can not only enhance the hydrophilicity and stability but also promote electron transfer and chemical reactivity, resulting in higher adsorption capacity and catalytic performance. − Shengli et al successfully synthesized Phragmites australis activated carbon (PAAC) . The maximum adsorption capacity of PAAC for HQ reaches 156.25 mg·g –1 , which is mainly attributed to the high specific surface area and rich N and O functional groups.…”