Gabriel Antonio Cerron-CalleYulu GeMariana Marcos-Hernandez
9页
查看更多>>摘要：Nitrate is a noxious and persistent oxyanion in drinking waters. It is themed as one of the most common water quality violations worldwide. Nitrate electrocatalytic reduction appears to be a viable solution. However, the use ot platinum group elements (PGEs) as electrocatalysts must be avoided due to their high cost and limited availability. In this study, earth-abundant nano-Fe3O4 electrodes were synthesized to surpass those implementation barriers. Surface functionalization has demonstrated to impact performance of inner sphere catalytic transformations but has been seldomly explored in the context of nitrate remediation. To understand the effect of the functionalization of Fe3O4 surfaces, Fe3O4 nano-enabled electrodes were functionalized with amine and carboxylic acids groups. After 360 min, the most promising results were obtained when the Fe3O4 surface was modified with carboxylic groups. The nitrate conversion obtained was ~ 90%, selectivity towards ammonia of ~ 55% and an electric energy per order (EE/O) of 37 kWh m~(-3) order~(-1). This EE/O value is ~ 2x lower, when compared to an experiment using a bare Fe-plate. Therefore, nano-Fe3O4 electrodes hold the potential of providing a green resource recovery process to treat nitrate pollution while recovering ammonia for its reuse as enriched water for crops irrigation.
查看更多>>摘要：Environmental pollution caused by oily wastewater, which frequently contains large amounts of organic dyes, has become increasingly serious. Super-wetting materials possessing special wettability have been widely used in membrane separation technology, with the excellent emulsion separation performance shown to be related to the specific surface morphology. In this study, metal-organic framework Mil-53(Fe) was successfully synthesized through solvothermal reaction and added to a precursor solution containing polyacrylonitrile powder for electrospinning. The resulting fibrous matrix membrane exhibites superamphilicity in air, superoleophobicity in water, and superhydrophobicity in oil, with separation efficiency for various oil-in-water emulsions reaching over 95%. Furthermore, this membrane exhibites self-cleaning and corrosion-resistant properties, and could be recycled after ten consecutive cycles. The degradation efficiency toward several organic dyes was simulated in visible light, combined with persulfate, achieving 100% degradation. Therefore, this membrane has potential applications in emulsion separation and dye degradation.
查看更多>>摘要：Pressurization pretreatment is reported as a novel pretreatment method for the coagulation removal of Microcystis sp. from eutrophicated water, as less coagulant is required than without pressurization. However, how cellular properties and algogenic organic matter (AOM) characteristics change with pressurization pretreatment and thus reduce the coagulant dose are still not understood. Using Microcystisflos-aquae in Lake Taihu, this study analyzed the changes in cellular morphology, size distribution, and charge density, as well as the changes in concentration and composition of cell-based protonated functional groups. Coagulation experiments using different combinations of cells and AOM with/without pressurization pretreatment showed that the changes in cell surface properties played a bigger role in coagulation enhancement than AOM. The enhancement of the coagulation efficiency of M.Jlos-aquae with pressurization pretreatment is related to the rupture of the mucilaginous sheath and subsequent exposure of cells with more active functional groups, the content of phosphodiester, carboxyl and phosphoryl functional groups on the surface of M.Jlos-aquae cells increased by 55%, 29% and 203%, respectively. Thus increasing the binding sites between M.flos-aqnae cells and cationic polyacrylamide (CPAM). As a result, with pressurization pretreatment, the dose of CPAM was reduced from 5 mg L~(-1) to 0.8 mg L~(-1) for the same removal efficiency of 90%. These results may help us understand the mechanism by which pressurization treatment impacts M.Jlos-aquae coagulation and thus provide a new perspective for the low-cost and sustainable removal of cyanobacterial blooms.
查看更多>>摘要：As the reuse of agricultural and forestry waste, leaf biochar can remove heavy metals from the environment, avoid secondary pollution while creating economic and environmental benefits for society. Our research presents an innovative approach to preparing efficient adsorbents for the first time using natural bioaugmentation (decay) pretreatment of fallen leaves biomass followed by pyrolysis to biochar. Compared with the pristine biochar derived from leaf (BC), the natural bioaugmentation biochar (NBC) characterization showed that the enhancement of microstructure increased the specific surface area, the change of surface composition increased the oxygen-containing functional groups and active adsorption sites, and the increase of porosity improved the mass transfer rate, resulting in a 2-fold increase of Cd(II) fixation capacity. Langmuir and pseudo-second-order models demonstrated that Cd(II) adhered to the NBC core sites through chemical reaction sites by a spontaneous process. The release of nutrients and changes in soil pH after NBC addition to contaminated soil enhanced the stability of the ecosystem and promoted plant growth. This study illustrates for the first time the great potential of natural bioaugmentation (decay) leaf-derived biochar for heavy metal adsorption and provides a new idea to explore the reuse of cellulose waste resources.
查看更多>>摘要：In the study, dielectric barrier discharge (DBD) plasma was used to activate peroxymonosulfate (PMS) for synergetic degradation of residual potassium ethyl xanthate (PEX) in mineral separation wastewater. The degradation efficiency of PEX in the combined system was obviously higher, indicating that the system had a significant synergistic effect on PEX degradation. After 25 min, approximately 90.5% of PEX and 1.637 of synergetic factors were achieved in the DBD/PMS system at 27.5 kV. The increase of PMS concentration resulted in the balance between the consumption and formation reaction of active species. The degradation efficiency of PEX under acidic conditions was higher. The addition of Cl~-, CO3~(2-) and HA had an inhibition effect on PEX degradat ion due to the consumption of·OH and·SO4~-, and the presence of Cu~(2+) promoted PEX degradation. The introduction of EtOH had a significant inhibitory effect, indicating that·S04" and·OH played a crucial part. The addition of PMS increased the dissolved 03 and H202 concentration in the combined system. The COD degradation and TOC mineralization efficiency gradually improved with the extension of treatment time for actual xanthate wastewater. A possible degradation pathway of PEX was proposed based on the degradation products.
查看更多>>摘要：The authors regret We have found, there is a problem with the image orders in the last version of the article that is being published online. In the accessible version, the caption of the images are exactly in the true orders, but the images are shifted up and they are not shown in their exact positions. This Corrigendumm is being released for revision of the image orders, like what they were in the accepted version of the manuscript. The materials are shown in the following pages.
查看更多>>摘要：Hybrid polysiloxane-polyamide thin-film composite (TFC) reverse osmosis (RO) membranes were produced in the presence of a zwitterionic silane compound during polyamide active layer preparation by interfacial polymerization for an enhanced desalination performance and chlorine resistance. The zwitterionic functional silane monomer, (3-sulfbpropylbetaine-propyl)-trimethoxysilane (SPPT), was added to an aqueous m-phenylenediamine (MPD) monomer solution at different concentrations;; 0.05, 0.1, 0.25, 0.5 and 1.0 SPPT/MPD ratios. The aqueous monomer solutions adsorbed on a polysulfone support layer were contacted with an organic trimesoyl chloride (TMC) monomer solution to create a polysiloxane-polyamide hybrid active layer by interfacial polymerization. Hybrid active layers were characterized by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), water contact angle (WCA), and zeta potential measurements. Membranes produced with a SPPT/MPD ratio of 0.1 exhibited an increase in permeate flux from 25 L m~(-2) h~(-1) to 33 L m~(-2) h~(-1) (55 bar operating pressure;; 3.2% NaCl feed) while the salt rejection was not compromised, but slightly increased from 98.8% to 98.9%, when compared to the control membrane prepared without SPPT. The highest resistance against chlorine was observed for the membranes produced with a SPPT/MPD ratio of 1.0, for which, a significant membrane damage and consequent loss of salt rejection were observed after six hours of exposure to chlorine solution, while the control membrane was prone to chlorine damage after two hours.
查看更多>>摘要：Advanced oxidation processes (AOPs) based on the metal-organic frameworks (MOFs) and peroxymonosulfate (PMS) have been demonstrated as promising methods for the degradation of contaminants. In this study, the degradation of bisphenol AF (BPAF) by activated PMS via ammo-modified metal-organic frameworks (AMOF) was investigated thoroughly. BPAF could be efficiently removed (94.1%) in the optimal condition. The decontamination of BPAF could be accelerated significantly with the increasing temperature, and a highly stable degradation performance was observed at a wide pH range. Quenching experiments and electron paramagnetic resonance (EPR) tests revealed that sulfate radical (SO4~-), hydroxyl radical (HO*), singlet oxygen (~1O2), and superoxide radical (O2~-) were produced synergistically in the AMOF/PMS system. Chloride ion (Cl~-) exhibited a dual influence on BPAF removal, while other anions and NOM could hinder the degradation rate mildly. A total of fifty-two intermediates were identified using UHPLC-MS/MS method and four main degradation pathways were proposed based on the density functional theory (DFT) calculation, including the frontier molecular orbital theory (FMO), natural population analysis (NPA), and Fukui function. Finally, the Quantitative Structure Activity Relationship (QSAR) method for Toxicity Estimation Software Tool (TEST) was applied to estimate the accurate toxicity of BPAF and degradation byproducts. This study exhibited the promising potential for the decontamination of BPAF in the water via the AMOF based AOPs.
查看更多>>摘要：Water recovery from flue gas with transport membrane condenser (TMC) has gained much attention in recent years. It has great potential in water conservation and air pollution control. However, effects of porosity and pore size variation of macroporous membranes on TMC application have not been revealed. Coal fly ash (CFA) is used as main raw material to prepare various tubular macroporous ceramic membranes for TMC application. The extrusion method is adopted. Characterization of membranes are conducted for structural parameters evaluation. Prepared membranes were used for TMC application to experimentally study the water and heat recovery performance. Influences of temperatures and flowrates of flue gas and cooling water on recovery performance have been investigated. Increasing cooling water flowrate and flue gas temperature, as well as decreasing cooling water temperature can promote water and heat recovery performance of TMC. The highest water recovery efficiency is 79.21%. Although membrane pore size increasing improves water and recovery, the average pore size should be less than 2 u,m to avoid transmembrane gas permeation. Results indicate that CFA membrane is suitable for TMC application and provides investment reduction.
查看更多>>摘要：According to the Pore-flow model describing the mass transfer process of Ultrafiltration (UF) membranes, the thickness of the separation layer directly determines the separation performance of an UF membrane;; pure water flux (PWF) and foulant rejection. However, the flexibility and limited supporting capacity of the conventional supporting layer (non-woven fabric) limits the further reduction of the separation layer thickness. In this study, stainless steel wire mesh (SSWM) was employed as the supporting layer to fabricate a metal/polymer composite UF membrane via a novel strategy denoted as "Quadratic Phase Inversion (QPI)", in which the SSWM was firstly modified with a casting solution with low PVDF concentration, and then another PVDF selective layer was constructed on the modified substrate with the conventional phase inversion method. Orthogonal experiment was conducted to optimize the fabrication parameters. A series of characterization was adopted to analyze the performance and structural evolution. The results demonstrate that a composite UF membrane with ultrathin PVDF selective layer could be fabricated on the PVDF modified SSWM. The optimized sample was obtained with the SSWM modification reagent of 3 wt% PVDF, the casting solution of 20 wt% PVDF, the casting thickness of 75 μm, and NMP as solvent, which had a MWCO of 149 kDa and mean pore diameter of 7.2 nm. Meanwhile, it presented a high PWF around 448.8 L m~(-2) h~(-1) bar~(-1), desirable BSA rejection about 96.3% and good operation stability. The outcome of this research is expected to provide a valuable route for promoting the separation performance of UF membranes.
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