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It has been a pressing challenge to treat saline wastewater with advanced oxidation techniques due to the inhibition of reactive oxygen species in the actual wastewater by co-existing ions. Herein, we synthesized TCPP@UiO-66(Hf) catalysts enriched with deletion linker defects by doping meso-tetra (4-carboxyphenyl) porphine (H2TCPP) in UiO-66(Hf) to modulate its performance for the removal of ofloxacin (OFL) from complex aqueous environment. TCPP@UiO-66(Hf)-250 promoted the removal efficiency of OFL from 13.4% to more than 96%. The adsorption and photocatalytic properties of TCPP@UiO-66(Hf)-250 with defects were significantly enhanced in various anionic environments. The electron-donating role of coexisting anions was investigated with SO42−as a representative. Quenching tests and electron paramagnetic resonance (EPR) revealed that in the TCPP@UiO-66(Hf)-250/Na2SO4/visible light (TCPP@UiO-66(Hf)-250/Na2SO4/VIS) system, O2∙−and 1O2dominated the removal of OFL with increasing levels. And SO4∙−was generated after the addition of SO42−, confirming the electron-donating role of sulfate in the photocatalytic system. The TCPP@UiO-66(Hf)-250/visible light (TCPP@UiO-66(Hf)-250/VIS) system maintained excellent OFL removal efficiency over a broad pH range of aqueous solutions, in high co-existing ion concentrations and actual aqueous matrices, and exhibited good performance in cycling tests. It demonstrates that the coexisting anions play an electron-donating role in the photocatalytic system and further reveals the synergistic mechanism between the photocatalyst and coexisting anions, which offers the possibility of contaminant removal in highly saline water.

A Co3O4-activated chlorite (Co3O4/chlorite) process was developed to enable the simultaneous generation of high-valent cobalt species [Co(IV)] and ClO2for efficient oxidation of organic contaminants. The formation of Co(IV) in the Co3O4/chlorite process was demonstrated through phenylmethyl sulfoxide (PMSO) probe and 18O-isotope-labeling tests. Both experiments and theoretical calculations revealed that chlorite activation involved oxygen atom transfer (OAT) during Co(IV) formation and proton-coupled electron transfer (PCET) in the Co(IV)-mediated ClO2generation. Protons not only promoted the generation of Co(IV) and ClO2by lowering the energy barrier but also strengthened the resistance of the Co3O4/chlorite process to coexisting anions, which we termed a proton enhancement effect. Although both Co(IV) and ClO2exhibited direct oxidation of contaminants, their contributions varied with pH changes. When pH increased from 3 to 5, the deprotonation of contaminants facilitated the electrophilic attack of ClO2, while as pH increased from 5 to 8, Co(IV) gradually became the main contributor to contaminant degradation owing to its higher stability than ClO2. Moreover, ClO2–was transformed into nontoxic Cl–rather than ClO3–after the reaction, thus greatly reducing possible environmental risks. This work described a Co(IV)-involved chlorite activation process for efficient removal of organic contaminants, and a proton enhancement mechanism was revealed.

Visible-light photocatalytic chlorite activation has emerged as an efficient oxidation process for micropollutant elimination. However, the in-depth mechanism of chlorite activation is not understood. In this study, using neodymium-doped bismuth vanadate (NdxBi1–xVO4-δ) as a model catalyst, we describe the oxygen vacancy (OV)-mediated chlorite activation process for efficient ClO2generation and cephalexin (CPX) degradation. DFT calculations and in situ DRIFTS suggest that the OV-introduced surface −OH serves as the Brønsted acidic center for chlorite adsorption. The OV-mediated chlorite activation involves multistep reactions that surface hydroxylation and proton transfer from the surface −OH to chlorite, forming metastable chlorous acid (HClO2) and further disproportionating to ClO2. As compared with vis-photocatalysis, the vis-photocatalysis coupled with chlorite activation (vis/chlorite) technique exhibits superior performance in antibiotic degradation and achieves efficient microorganism inactivation. This work uncovers the role of OVs on chlorite activation and provides a rational strategy for designing visible-light-driven oxidation techniques in water and wastewater treatment.

Efficient conversion of straw cellulose to chemicals or fuels is an attracting topic today for the utilization of biomass to substitute for fossil resources. The development of catalysts is of vital importance. In this work, a composite catalyst metal-organic frameworks (MOFs) immobilized on three-dimensional reduced graphene oxide (3D-rGO) were synthesized by in situgrowth of the MIL-101(Cr) within the 3D-rGO matrix. The supporting of 3D-rGO guaranteed the dispersion and acid site density of MIL-101(Cr). The MIL-101(Cr)@3D-rGO nanocomposite possesses excellent catalytic activity, stability, recyclability and is an idea catalyst for the efficient degradation of straw cellulose into formic acid (FA), acetic acid (AA) and oxalic acid (OA). A maximum FA conversion rates of 95.36% was obtained by using MIL-101(Cr)@3D-rGO(1:1) as catalyst and hydrothermal reaction at mild conditions of 200 °C for 1h in alkaline aqueous medium. The MIL-101(Cr)@3D-rGO nanocomposite can be reused with high catalytic activity without any collapse of structure or leaching of chromium.

• The straw cellulose hydrogel beads were prepared by regenerating wheat straw cellulose from ionic liquid. • SCHBs presented perfect adsorption capacity for Cd(II). • The spent adsorbent SCHBs-Cd(II) was in-situ recycled to SCHBs-CdS nanocomposite photocatalyst. • The SCHBs -CdS nanocomposite showed excellent photodegradation activity under visible light. Environment-friendly straw cellulose hydrogel beads (SCHBs) were applied for Cd(II) recovery and recycling from solution. The SCHBs presented good adsorption capacity for Cd(II) of 95.62 mg/g at 313.5 K. These Cd(II) loaded SCHBs were recycled for CdS in-situ synthesis and employed as photocatalyst in the degradation of methylene blue under visible light irradiation. Both TEM and SEM images confirmed that the recycled CdS nanoparticles within SCHBs are smaller than 20 nm in size, and XRD patterns were consistent with the metallic crystallinity of CdS. The recycled SCHBs-CdS composites exhibited excellent photocatalytic degradation ability and reusability. [ABSTRACT FROM AUTHOR]

Hydrothermal vents bacteria naturally adapted to high temperature and high salinity environments may provide a new idea for the treatment of industrial wastewater with extreme conditions. In this study, a high-salinity and high-temperature resistance bacteria, Pseudomonassp.4–2 was isolated from a deep-sea hydrothermal vent, and proved having good adsorption efficiency for Pb2+through batch experiments. The maximum adsorption capacity of Pb2+was 226.24 mg/g at 55 ℃ for active cells, while it was 204.91 mg/g for inactivated cells at 35 ℃ (5% w/v NaCl, pH 6.0 and 0.2 g/L biosorbent dose). The adsorption was a spontaneous endothermic reaction that had the best fit with Langmuir isotherm model and the pseudo-second-order kinetic model. The biosorption process was studied by SEM-EDS, TEM, XRD, XPS, VTIS and 2D-COS analysis, showing that PbS and Pb(OH)2precipitates were mainly species formed during the adsorption process, and the percentage of PbS was significantly higher than Pb(OH)2. For the molecular structure of the strain 4–2, the respond degree from large to small was lipids, polysaccharides and proteins, the response sequence was proteins, lipids and polysaccharides. The molecular structure of polysaccharides may be the main factor affecting the thermostability and adsorption efficiency at high temperatures. Diffusion, surface adsorption, micro-precipitation, complexation and intracellular accumulation (only active cells) were involved in the adsorption process. Pseudomonassp. 4–2 may expand the bacterial resource library for microbial remediation and facilitate the development of novel treatment method for extreme industrial wastewater.

AbstractBiosorption behavior and mechanism of an exopolysaccharide (EPS) secreted by a psychrotolerant bacterium Pseudoalteromonassp. Bsi20310 isolated from Antarctic sea-ice, for lead(II) from synthetic wastewater were studied in this paper. Effects of salinity, pH and dosage of Bsi20310 EPS on biosorption characteristics for lead(II) were evaluated by batch biosorption tests. The results indicated that Bsi20310 EPS presented better biosorption performance for lead(II) in salt water than in salt-free water. The equilibrium biosorption isotherms fitted well to both Langmuir and Freundlich isotherm models. Theoretical maximum biosorption capacity of 191.90 mg g−1calculated according to Langmuir equation indicated that Bsi20310 EPS had a high biosorption capacity for lead(II). The kinetics of lead(II) biosorption onto Bsi20310 EPS could be better described by pseudo-second-order model than pseudo-first-order both in salt-free water and in salt water. External surface biosorption was the major biosorption echanism while intraparticle diffusion was not the unitary rate-limiting step for the whole biosorption. Fourier transform infrared spectroscopy (FT-IR) analysis indicated that the functional groups such as –OH, C=O and C–O–C on Bsi20310 EPS may play important roles as biosorption sites in lead(II) biosorption.

Biosorption behavior and mechanism of an exopolysaccharide (EPS) secreted by a psychrotolerant bacterium Pseudoalteromonassp. Bsi20310 isolated from Antarctic sea-ice, for lead(II) from synthetic wastewater were studied in this paper. Effects of salinity, pH and dosage of Bsi20310 EPS on biosorption characteristics for lead(II) were evaluated by batch biosorption tests. The results indicated that Bsi20310 EPS presented better biosorption performance for lead(II) in salt water than in salt-free water. The equilibrium biosorption isotherms fitted well to both Langmuir and Freundlich isotherm models. Theoretical maximum biosorption capacity of 191.90 mg g-1calculated according to Langmuir equation indicated that Bsi20310 EPS had a high biosorption capacity for lead(II). The kinetics of lead(II) biosorption onto Bsi20310 EPS could be better described by pseudo-second-order model than pseudo-first-order both in salt-free water and in salt water. External surface biosorption was the major biosorption mechanism while intraparticle diffusion was not the unitary rate-limiting step for the whole biosorption. Fourier transform infrared spectroscopy (FT-IR) analysis indicated that the functional groups such as –OH, C=O and C–O–C on Bsi20310 EPS may play important roles as biosorption sites in lead(II) biosorption.

Wangia profunda SM-A87, representative of a new genus of family Flavobacteriaceae, was isolated from deep-sea sediment samples near the southern Okinawa. The exopolysaccharides (EPS) produced by W. profunda SM-A87was used as an absorbent of Pb(II) from low concentration solution in this paper. The effect of various parameters such as EPS concentration, pH, temperature, contact time, ionic strength and the competitive adsorption of Pb(II), Cu(II), Cd(II) were evaluated in batch technique. The adsorption kinetic and isotherm were also calculated. The preferences biosorption conditions were, EPS dosage at 0.1~0.2 mg/l, pH value at 5.5, temperature at 20~30°C and contact time for 60 min, respectively. Coexistent cations decreased Pb(II) uptake in the order of K+

Wangia profunda SM-A87, representative of a new genus of family Flavobacteriaceae, was isolated from deep-sea sediment samples near the southern Okinawa. The exopolysaccharides (EPS) produced by W. profunda SM-A87was used as an absorbent of Pb(II) from low concentration solution in this paper. The effect of various parameters such as EPS concentration, pH, temperature, contact time, ionic strength and the competitive adsorption of Pb(II), Cu(II), Cd(II) were evaluated in batch technique. The adsorption kinetic and isotherm were also calculated. The preferences biosorption conditions were, EPS dosage at 0.1~0.2 mg/l, pH value at 5.5, temperature at 20~30°C and contact time for 60 min, respectively. Coexistent cations decreased Pb(II) uptake in the order of K+