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[Display omitted] • Experimental and theoretical investigation for the competitive adsorption and mechanism. • Site energy distribution of the adsorption system was determined. • Adsorption affinity was assessed by the average site energy. • Adsorption process was visualized by molecular simulation. Concerns about antibiotic contamination have grown dramatically. Based on batch adsorption equilibrium experiments, the adsorption properties and mechanisms of two antibiotics, namely Tetracycline (TC) and erythromycin (ERY), on the typical clay montmorillonite (Mt) were investigated in single and binary systems. Results indicated that the adsorption of both antibiotics on Mt was a multistage process control and charge-limited intercalation. It was also clearly demonstrated the presence of the competitive adsorption between TC and ERY on the active sites of Mt. Moreover, the site energy theory and electrostatic potential (ESP) distribution were used to quantify the adsorption sites, interaction force and electrostatic attraction between Mt and antibiotics, elucidating that TC had a relatively strong competitiveness than ERY. Additionally, combined with FT-IR, XRD and molecular simulation, the adsorption process was simulated to investigate the conformational behavior of antibiotics in the confined space of Mt. These results and methodologies can aid to further study the migration-transformation of antibiotics in the environment. [ABSTRACT FROM AUTHOR]

The surface NH 2 -grafting on activated carbon (AC), N-doping into TiO 2 and dense interfacial heterojunctions between AC and TiO 2 were achieved synchronously by treating of TiO 2 /AC with ethylenediamine. The obtained materials were characterized and applied for the removal of aqueous Cr(VI) through their adsorption and visible-light-driven photoreduction. Results obtained showed that ethylenediamine was grafted covalently onto AC through amide linkage, and simultaneously, served as the precursor of nitrogen doped into TiO 2 . Improved performance of modified TiO 2 /AC for Cr(VI) removal was acquired, which can be attributed to the multiple roles of ethylenediamine modification at TiO 2 /AC as: to enhance the adsorption capability of AC for Cr(VI) through electrostatic, coordinative and hydrogen bonding; to extend and intensify the optical absorption on TiO 2 ; to promote the forming of dense heterojunctions between TiO 2 and AC through Ti – O – C linkages, facilitating the intimate contact and fast interfacial mass transfer of Cr(VI) and photo-generated electrons between AC and TiO 2 . [ABSTRACT FROM AUTHOR]

TiO 2 coated on activated carbon (TiO 2 /AC) was synthesized by a facile sol-hydrothermal preparation. The as-prepared TiO 2 /AC was modified by sequential treatment of nitric acid and thionyl chloride, followed by surface attaching of diethylenetriamine. The obtained materials were characterized by transmission electron microscopy, Fourier transform-infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, BET adsorption, and their adsorption–photocatalytic reduction activities were evaluated by the removal of aqueous Cr(VI). The results showed that TiO 2 particles were homogeneously deposited on the surface of activated carbon, and diethylenetriamine was grafted covalently onto the surface of TiO 2 /AC through amide linkage. The diethylenetriamine-functionalized TiO 2 /AC (TiO 2 /AC-DETA) exhibits high adsorption capability for Cr(VI) through electrostatic, coordinative and hydrogen bonding interactions. The significant enhancement of photocatalytic activity of TiO 2 /AC-DETA for reduction of Cr(VI) was observed, which was mainly attributed to the enrichment of Cr(VI) onto the surface of AC and successive fast interfacial transfer of Cr(VI) and photogenerated electrons resulted from the intimate contact between AC and TiO 2 through dense heterojunctions by forming of C–O–Ti linkages. [ABSTRACT FROM AUTHOR]

Fe-based metal organic frameworks (Fe-MOFs) being a newly developed photo-Fenton catalyst, have gained ever-increasing attention for environmental remediation, but have been limited by high synthesis cost (high energy-consumption and low yield). In this work, economical and scalable synthesis of Fe-BDC 1 (BDC denotes as terephthalic acid) was achieved via facile stirring under ambient condition, and its adsorptive, photocatalytic, Fenton-like and photo-Fenton performances were comprehensively explored against contaminants removal. In comparison, synthesized Fe-BDC 2 with the common solvothermal method, the yield of Fe-BDC 1 increased 3.4 times. Also, its adsorption capacity towards Rhodamine B (Rh. B) increased about 5.85 times. Moreover, the significantly improved degradation of Rh. B was observed in the Fenton-like and photo-Fenton systems with the increased reaction rate constants up to 4.90 and 2.33 times, respectively. This enhanced catalytic performance of Fe-BDC 1 was mainly attributed to the enlarged specific surface area (SSA) and favorable electron separation and migration, resulting into the accelerated ≡Fe(II)/≡Fe(III) cycle and increased yield of reactive oxidative species (ROSs). Additionally, the unique light-induced adsorption enhancement further strengthened the contaminants removal. Fe-BDC 1 as photo-Fenton catalyst was found superior over conventional catalysts in terms of advantages including: low dose requirement of catalysts (decrease in an order of magnitude) and H 2 O 2 , wide pH working range (3.0–9.0), excellent reusability and stability, universal removal behavior against all organic pollutants, and remarkable synergism between photocatalysis and Fenton-like process with synergistic factor of 77.23%. Moreover, the Fe coordinative unsaturated sites (Fe CUSs) and ·OH were determined as the active sites and the main ROSs, respectively, responsible for highly efficient pollutant degradation. This work gives a feasible solution for the preparation of Fe-MOFs with low synthesis cost and high yield, paving ways for their practical mass application in heterogeneous photo-Fenton oxidation. [Display omitted] • Successfully synthesis of Fe-MOFs with low cost and high yield. • Significantly enhanced adsorption, Fenton-like and photo-Fenton performances were acquired. • Visible light induced adsorption enhancement further strengthen contaminates removal. • The synergism between photocatalytic and Fenton-like process was demonstrated. • Favorable electron separation and migration accelerated ≡Fe(II)/≡Fe(III) cycle. [ABSTRACT FROM AUTHOR]