Synergistic removal of copper and tetracycline from aqueous solution by steam-activated bamboo-derived biochar.

Steam-activated biochar (SBC) was prepared and showed excellent performance for synergistic removal of Cu2+ and tetracycline (TC). The adsorption capacity of SBC and mutual effect of TC and Cu2+ were investigated via single and binary system and the adsorption isotherm. The adsorption capacity of TC was significantly enhanced when it coexisted with Cu2+. Likewise, increased amounts of Cu2+ were adsorbed in the presence of TC. The presence of NaCl exerted a negative influence on the adsorption of Cu2+, while the inhibitory effect of salinity on TC was neutralized by bridge enhancement in the binary system. Bridge enhancement and site competition were involved in the synergistic removal of TC and Cu2+. Considering the stable application in simulated and real water samples, SBC showed great potential for synergistic removal of antibiotics and heavy metals.

Insights into the effect of chemical treatment on the physicochemical characteristics and adsorption behavior of pig manure-derived biochars.

Chemical treatment could improve the adsorption performance of biochars (BC). In order to deal with Pb(II) pollution, four types of biochars including unmodified, acid-treated, alkali-treated, and magnetic-treated pig manure-derived biochars (PBCs) were prepared. The effect of chemical treatment on the physical property, chemical composition, and the adsorption behavior of biochars was compared. Magnetic and alkali treatment improved pore volume and specific surface areas, and the adsorption capacity and rates were enhanced. In contrast, the adsorption capacity of acid-treated BC decreased due to the significant decrease of ash content. The magnetic samples displayed the satisfactory absorption performance, which could achieve 99.8% removal efficiency within 15 min at a Pb(II) concentration of 50 mg/L. Considering its properties of excellent adsorption performance, fast reaction rate, and convenient recovery by an external magnetic field, magnetic biochar based on pig manure may provide an effective way to remove heavy metals and decrease the pig manure solid waste.

Investigating the adsorption behavior and the relative distribution of Cd2+ sorption mechanisms on biochars by different feedstock.

The objective of this study was to investigate the adsorption behavior and the relative distribution of Cd2+ sorption mechanisms on biochars by different feedstock. Bamboo biochars (BBCs), corn straw biochars (CBCs) and pig manure biochars (PBCs) were prepared at 300-700 °C. Adsorption results showed PBCs have the best adsorption capacity for Cd2+, the extra adsorption capacity of PBCs mainly attributed to the precipitation or cation exchange, which played an important role in the removal of Cd2+ by PBCs. The contribution of involved Cd2+ removal mechanism varied with feedstock due to the different components and oxygen-containing functional groups. Cd2+-π interaction was the predominant mechanism for Cd2+ removal on biochars and the contribution proportion significantly decreased from 82.17% to 61.83% as the ash content increased from 9.40% to 58.08%. Results from this study may suggest that the application of PBC is a feasible strategy for removing metal contaminants from aqueous solutions.

Application of molecularly imprinted polymers in wastewater treatment: a review.

Molecularly imprinted polymers are synthetic polymers possessing specific cavities designed for target molecules. They are prepared by copolymerization of a cross-linking agent with the complex formed from a template and monomers that have functional groups specifically interacting with the template through covalent or noncovalent bonds. Subsequent removal of the imprint template leaves specific cavities whose shape, size, and functional groups are complementary to the template molecule. Because of their predetermined selectivity, molecularly imprinted polymers (MIPs) can be used as ideal materials in wastewater treatment. Especially, MIP-based composites offer a wide range of potentialities in wastewater treatment. This paper reviews the latest applications of MIPs in wastewater treatment, highlights the development of MIP-based composites in wastewater, and offers suggestions for future success in the field of MIPs.