3D Wood Microfilter for Fast and Efficient Removal of Heavy Metal Ions from Water

Abstract

Adsorption is an effective method for the treatment of heavy metal ions in water; however, the existing adsorbents are complicated to prepare, and costly and difficult to recover. In this work, a 3D wood microfilter was prepared by modifying wood for the removal of heavy metal contaminants from water. First, a green deep eutectic solvent was used to remove lignin from beech wood. Then citric acid and l-cysteine were sequentially used to graft carboxyl and sulfhydryl groups (−SHs) on the surface of cellulose. Finally, a three-dimensional wood microfilter with an abundant porous structure and adsorption sites was formed. The adsorption kinetics and adsorption isotherms of heavy metal ions on the 3D wood microfilter were systematically investigated using Cu2+ and Cd2+ as model species. The results showed that the 3D wood microfilter had a fast adsorption rate and high saturation capacity for both Cu2+ and Cd2+. Based on the advantages of easy processing and multilayer assembly and stacking, a three-layer wood microfilter was designed to achieve high flux rate (1.53 × 103 L m–2 h–1) and high efficiency (>98%) for the removal of heavy metal ions in water. The enhancement mechanism of the adsorption process of Cu2+ and Cd2+ by the 3D wood microfilter was investigated using SEM and EDS, FTIR, and XPS characterization. The simple synthesis method and high adsorption efficiency of this wood microfilter provide a new strategy for the preparation of cheap, efficient, and recyclable adsorbents for heavy metal ions in water.

Synthesis of Aminomethylpyridine-Decorated Polyamidoamine Dendrimer/Apple Residue for the Efficient Capture of Cd(II)

“…After modification of AP with EPI, the epoxy peak appeared in the spectrum of AP-E at 1254 cm –1 , which suggests that the chemical modification was successful . After functionalization of AP-E with EDA, the characteristic absorption of epoxy disappears and the absorption of C–N groups appears at 1371 cm –1 in the spectrum of AP-NH 2 in Figure (a), which demonstrates that the reaction between AP-E and EDA was achieved. , The characteristic absorption of carbonyl ester groups is observed at 1733 cm –1 in the spectrum of AP-G0.5 in Figure (b), which suggests that the Michael addition reaction between AP-NH 2 and MA was successful. , The absorption peak of carbonyl ester groups disappears in the spectrum of AP-G1.0, which proves that the amidation of EDA with AP-G0.5 was successful. Meanwhile, the absorption peak at 1604 cm –1 was attributed to the amide group, which further demonstrated the successful synthesis of AP-G1.0. , The FTIR spectrum of AP-G1.5 is similar to that of AP-G0.5, demonstrating that the synthesis of AP-G1.5 was also achieved.…”

“…Many methods, including chemical precipitation, adsorption, membrane separation, and reverse osmosis, were employed for decontaminating aqueous Cd­(II). , Adsorption is recognized as an efficient method owing to the merits of simple operation, high efficiency, and easy regeneration of the adsorbents . Various adsorbents were fabricated to adsorb Cd­(II) from water solutions, such as silica, carbon nanotubes, chitosan, graphene, biochar, montmorillonite, and cellulose nanofiber membranes .…”

Research Advances in Wood Composites in Applications of Industrial Wastewater Purification and Solar-Driven Seawater Desalination

“…In order to improve the adsorption capacity, adsorption efficiency and selectivity of wood as adsorbent, other functional groups or inorganic nanomaterials can be further grafted or loaded in the wood channels. He et al [ 21 ] prepared a 3D wood microfilter by modifying wood for the removal of heavy metal pollutants in wastewater. Specifically, a green deep eutectic solvent was used to remove lignin from beech wood.…”

“…Reprinted with permission from Ref. [ 21 ]. Copyright 2020 ACS Publications Ltd. ( b ) SH-wood membrane, including a magnified drawing of its microstructure and chemical composition [ 22 ].…”

“…Then, three layers of composite membranes were assembled together as a composite filter. Compared with the results of Yang et al [22], the treatment rate of the device towards simulated wastewater containing Cu 2+ and Hg 2+ is 1.3 × 10 2 Schematic of SH-wood stacks for heavy metal ion removal from aqueous solution [21]. Reprinted with permission from Ref.…”