查看更多>>摘要：Nitrogen-doped biochar encapsulating Fe/Mn nanoparticles (Fe/Mn@NBC800) was synthesized as a cost-effective catalyst for activating peroxymonosulfate (PMS) towards the degradation of bisphenol-A (BPA). Superior catalytic performance of Fe/Mn@NBC800 was observed as BPA was completely degraded within 20 min and with a reaction rate 75.88-fold higher than that of pristine biochar. This observation ascribed to redox cycles between Fe and Mn with multivalent states and nitrogen functionalization in Fe/Mn@NBC800, accelerating the electronic migration in the activation of PMS. Further investigation indicated radical pathways, especially SO4 center dot- and (OH)-O-center dot serve a predominant role in the oxidative decomposition of BPA. Also, O-2(center dot-) and non-radical (O-1(2)) assumed an indispensable role in this process. Environmental factors had little effect on the synergistic process of radical and non-radical. The potential BPA degradation pathway was inferred by Density Functional Theory (DFT) calculation and intermediates analysis. In terms of excellent separability, reusability, stability, and universality, Fe/Mn@NBC800 exhibited promising application prospects.
查看更多>>摘要：In this work, Ni(II) was used as peroxymonosulfate (PMS) activator for decomplexation of Ni(II)-citrate, and subsequently applied for the decomplexation of chelated nickel in the electroless nickel plating wastewater. Effect of the co-existed substances (HCO3-, HPO32-, H2PO2-, and P2O74-) on the decomplexation of Ni(II)-citrate were evaluated. Interestingly, except for H2PO2-, the presence of HCO3-, HPO32-, and P2O74- enhanced the decomplexation efficiency of Ni(II)-citrate via promoting the decomposition of PMS. Based on the radical quenching experiments and electron spinning resonance (ESR) spectra analysis, (OH)-O-center dot, SO4 center dot-, and O-1(2) were the primary reactive species involved in the decomplexation reaction process. Furthermore, after the decomplexation of the electmless nickel plating wastewater by PMS, the recovery of nickel was successfully achieved via adsorption coupled with electrodeposition, and 93.1% nickel recovery could be accomplished with initial Ni (II) eluent concentration of 32.5 g/L. Therefore, this study provides a green and promising approach for the application of advanced oxidation processes based on PMS activation, and has the potential to convert recoverable resources into value-added products from electroplating wastewater.
查看更多>>摘要：Effective wastewater cleaning methods are required to reduce environmental pollution and harmful human health effects. Here, a bauxite residue/MoS2 (BR-MoS2) composite is prepared via a one-step hydrothermal method using industrial waste residue (i.e., BR). The hydrothermal reaction time was varied to tune MoS2 coverage content and optimize the capacity for light absorption and organic dye adsorption. Under the synergistic effect of adsorption and photocatalysis, the proposed low-cost BR-MoS2 composites effectively improved the removal of organic pollutants from wastewater. Furthermore, BR-MoS2 demonstrated an improved optical absorption and photo-induced electron transfer as compared with that of a bare CM photocatalyst. The optimized BR-MoS2-12 h (with a hydrothermal reaction time of 12 h) demonstrated high photocatalytic degradation efficiency for dyes under light irradiation and excellent recyclability. To summarize, the proposed catalyst advances the research of cost-effective and sustainable wastewater treatment methods.
查看更多>>摘要：This work gives an outline of current research patterns in bio-oil separation techniques and their applications. Due to unpredictable nature of bio-oil, various challenges have been reported in downstream operations. Several methods have been presented to redesign the bio-oil by separating the combination of bio-oil compounds into a group of chemical substances and portions advanced in definite groups of chemical mixtures. In this review, different separation strategies for bio-oil such as fractionation, water extraction, organic solvent extraction, supercritical fluid extraction, and membrane separation, with the qualities of bio-oil extracts and their applications have been discussed. It was found that the most favorable techniques are fractionation and organic solvent extraction. The present review focuses on recent developments made from model mixtures present in biooil as well as pyrolysis bio-oil; techno-economical analysis has been presented for researchers who are expected to bridge knowledge gap and for industrial practitioners.
查看更多>>摘要：The evaporation of desulfurization wastewater (DW) using hot flue gas is an effective treatment method for DW. However, its application is limited owing to a slow evaporation rate and formation of fine crystalline particles. To increase the evaporation rate of DW and the agglomeration efficiency of fine particles, a technology for the evaporation of charged DW droplets was proposed and investigated. The influence of factors such as induction electrode voltage, atomization pressure, and Cl- concentration on the agglomeration of fine particles and the charge transfer characteristics between droplets and particles was studied. The results showed that increasing the induction electrode voltage and atomization pressure and reducing Cl- concentration improved the agglomeration efficiency of fine particles. Compared to the uncharged droplet conditions, the agglomeration efficiency of fine particles increased by 57.12% under conditions of 12 kV induction electrode voltage, 0.3 MPa atomization pressure, and 20 g/L Cl- concentration. The relative agglomeration efficiency of the ultra-fine particles and particles in the 0.1-1 mu m size range also increased. After evaporation of the charged DW droplets, most of the electric charge of the droplets remained on the dry agglomerated particles. Agglomerated particles exhibited characteristics of chains and irregular clusters, and were tightly connected by solid bridges. The study results confirmed the feasibility of using the atomization of charged droplets to treat DW more effectively and improve the agglomeration efficiency of fine particles.
查看更多>>摘要：In this research, metal-organic frameworks ZIF-8 nanoparticles, which is synthesized via the liquid phase method, exhibits the outstanding piezocatalytic performance on Rhodamine B (RhB) dye degradation under vibration. The piezocatalytic degradation ratio of RhB dye (5 mg/L) can reach similar to 94.5% after undergoing 90 min vibration. ZIF-8, with the coexistence of cubic phase and monoclinic phase, confirmed from XRD, is piezoelectric in theory, which contributes to the excellent piezocatalytic performance. The main active species, which plays an important role in piezocatalytic process, are the superoxide radicals (center dot O-2(-)), the positive charges (q(+)) and the negative charges (q(-)) on basis of the active species quenching experiment results. The MOF material ZIF-8 is potential in the application field of the highly piezocatalytic dye wastewater degradation under vibration.
查看更多>>摘要：In-situ generation of iron catalysts in electro-Fenton (EF) process deserves more attention like in-situ generation of H2O2. In this work, a novel induced zero-valent iron (ZVI) electrode, which was composed of a graphite plate with good conductivity, ZVI powders and a small magnet, was for the first time designed through magnetic assembly. Fe2+ could be slowly generated in-situ from induced ZVI electrode and effectively trigger EF oxidation of chlorobenzenes (CB) under neutral pH. Compared to the in-situ rapid release of Fe2+ from sacrificial anodes and traditional one-time external dosing of Fe2+ in EF, in-situ slow release of Fe2+ from induced ZVI electrode was the most effective way to activate electrogenerated H2O2 under neutral pH. Induced ZVI electrode had obvious advantages in terms of effective active areas, corrosion potentials and current responses. The optimum conditions including pH of 7.0, current of 29.9 mA, ZVI of 0.10 g and electrolysis time of 35.25 min were obtained by the response surface methodology (RSM) model with the maximum removal efficiency of 99.12%. The uniformed weak positive charge on the ZVI powders induced by the electric field was the dominant contribution to the in-situ slow release of Fe2+ from the induced electrode. And, the impact of magnetic field on the CB removal and the release of iron ions was negligible. The degradation mechanism was revealed through the Fukui function based on the density functional theory (DFT) and by-products analysis. The evolution of acute toxicity to zebrafish in EF was further clarified. Besides, this induced ZVI electrode could be easily reused and has satisfactory stability. In briefly, this work provided a novel idea for the in-situ slow release of Fe2+ in EF process.
查看更多>>摘要：The synergistic Zr4+ doping and PANI coupling were used to improve the photocatalytic activity of SnS2 nanoflakes for the treatment of aqueous Cr (VI). The Zr-SnS2/PANI photocatalyst was prepared by a facile two-step method. The optimal Zr-SnS2/PANI-6% (with the Zr/Sn molar ratio of 1:8 and the PANI content of 6 wt%) exhibited dramatically higher photocatalytic activity toward Cr (VI) reduction than SnS2, Zr-SnS2, SnS2/PANI, and many previously reported SnS2-based and PANI-containing visible-light photocatalysts. Moreover, Zr-SnS2/PANI-6% showed outstanding performance in the photocatalytic treatment of Cr (VI)-containing electroplating solution. Based on the measured photo-electrochemical properties of the samples, the increased photocatalytic efficiency of Zr-SnS2/PANI-6% was mainly due to the synergistic effect induced by the smaller bandgap, higher charge transfer efficiency, and lower electron-hole recombination rate. Furthermore, the effects of coexisting cations and anions, photocatalyst amount, initial pH, Cr (VI) concentration, environmental atmosphere, and copresence of 1,4-benzoquinone or K2S2O8 on photocatalytic Cr (VI) reduction over Zr-SnS2/PANI-6% were investigated.
查看更多>>摘要：Bio-fouling of membranes caused by microorganisms seriously limited the development of membrane technology in practical applications. Design and synthesis of antifouling and antibacterial membranes with high quality are of paramount importance. In this study, we report a facile and safe method of extended Mitsunobu reaction (EMR)-freeze drying (FD) method to achieve oxygen-containing azido functionalized GO (AGO) nanosheets and synthesize novel azido-group functionalized graphene/polysulfone mixed matrix ultrafiltration membranes with enhanced permselective, antifouling and antibacterial property. Unlike reported thermochemical or chemical reactions to modify GO nanosheets, GO nanosheets were functionalized at low temperature which effectively prevented the decomposition of structural frame of pristine GO materials and the self-stacking phenomenon. Because of strong interactions between oxygen-containing AGO nanosheets and polymer matrices, high dispersity and interfacial compatibility were obtained in polysulfone membranes, resulting in sharp decrease of interfacial defects. Different kinds of techniques include SEM, ATR-FTIR, XPS, XRD, TEM and EDX were used to investigate the structure and morphology of AGO nanosheets and blended membranes, and cross-flow filtration experiments, anti-fouling and antibacterial test were applied to predict the behavior of hybrid membranes. High performance AGO/PSF mixed matrix membranes with excellent anti-fouling ability were successfully synthesized, which exhibited pure water flux as large as 245.1 L m(-2)h(-1) with satisfactory rejection of 95.8% for BSA. Moreover, the prepared membranes displayed good antibacterial activity against E. coli and S. aureus in long-term duration.
查看更多>>摘要：Tight ultrafiltration (TUF) membranes have been proposed as an effective candidate for the treatment of textile wastewater with high salinity. In this study, a novel polysulfate (PSE)-based TUF membrane was prepared by coupling the non-solvent induced phase separation (NIPS) process with the physical aging method. The polyvinylpyrrolidone (PVP) was adopted to tailor the micro-/nanostructure of the fabricated membranes. Accordingly, the molecular weight cut-off (MWCO) of the membrane can be tuned from 293.8 to 3.7 kDa. Endowed with the high porosity and small pore size, the optimized PSE/PVP blend membrane (a MWCO of 3.9 kDa) was applied for removal of dyes from dye/salt aqueous solution, which offered top-tier overall performance, e.g., a pure water flux of 70.7 L*m(-2)*h(-1), CR/NaCl selectivity of 494.3, CR/Na2SO4 selectivity of 42.6, long-term running stability, and excellent antifouling performance. Therefore, our study establishes a simple avenue to fabricate a high-performance TUF membrane for practical textile wastewater treatment.
NSTL
Elsevier