Treatment of phenol wastewater using nitrogen-doped magnetic mesoporous hollow carbon

Nitrogen-doped magnetic mesoporous hollow carbon (NMMHC) was prepared to realize effective adsorption of phenol from wastewater. The chemical and physical properties of NMMHC were analyzed, and the effects of adsorption time, initial pH, and phenol concentration on the adsorption capacity of NMMHC were studied. Adsorption kinetics and isotherm models were used to explain the adsorption properties. The results showed that the specific surface area, type of nitrogen group, and nitrogen content of NMMHC are related to the carbonization temperature. Chemical interaction was demonstrated to be present in the process of adsorption, which was characterized as monolayer adsorption. In addition, the adsorption mechanism was studied by attenuated total internal reflectance Fourier transform infrared spectroscopy and analysis of non-covalent interactions. This study found that non-covalent interactions between NMMHC and phenol molecules are van der Waals interactions, and nitrogen-containing groups increase the phenol adsorption capacity by enhancing such interactions. The π-π interactions between the nitrogen groups and phenol molecules also enhanced the adsorption energy.

Rattle-type magnetic mesoporous hollow carbon as a high-performance and reusable adsorbent for water treatment

Rattle-type magnetic mesoporous hollow carbon (RMMHC) materials have shown great promise as adsorbents for water treatment. In this work, we report a surfactant-free synthesis of RMMHC nanoparticles (NPs) using magnetite NPs as the core, tetrapropyl orthosilicate, resorcinol and formaldehyde to form the shell followed by carbonization and selective silica etching. The pore size, specific surface area and pore volume of RMMHC NPs can be tuned by varying the carbonization temperature (500, 700 and 900 °C). At the optimized temperature of 700 °C, the RMMHC NPs possess the highest specific surface area of 579 m² g^-1, the largest pore volume of 0.795 cm³ g^-1, and the largest pore size of 7.6 nm among all three samples. The adsorption capacity of optimized RMMHC NPs towards di (2-ethylhexyl) phthalate (a model organic pollutant) reaches as high as 783.1 mg g^-1. Taking advantage of the magnetic property, the adsorbents retain more than 87% of their initial adsorption capacity over five times' reuse.

Cerium functionalized PVA–chitosan composite nanofibers for effective remediation of ultra-low concentrations of Hg(ii) in water

Functionalized PVA–chitosan composites nanofibers effective for removal of very low concentration of mercury.

Dye adsorbed on copolymer, possible specific sorbent for metal ions removal

The efficiency of styrene-divinylbenzene functionalized with trimethylamonium groups as sorbent for the direct dye removal from aqueous solutions was investigated.