查看更多>>摘要：Electroreduction of nitrate is a promising approach and attracting increasing attention in recent years. However, most studies focus on conventional planar electrodes whose flat structure causes limited mass transfer and low nitrate reduction efficiency. Herein, we prepared a novel Cu-containing particle-embedded 3D open porous carbon foam monolith (3D-PCF) electrode for electroreduction of nitrate. The 3D-PCF was prepared by foaming of molten sucrose, followed by dehydration and carbonization. Then Cu-containing particle was in-situ fabricated on the 3D-PCF using a hydrothermal procedure and a subsequent annealing treatment. Benefitting from the advantages of 3D open porous architecture, highly active interface and excellent electron conductivity of the carbon skeleton, the optimized electrode exhibited 99.9% nitrate removal efficiency in 1 h and 100 % N2 selectivity with the aid of chlorine oxidation in 3 h. The reduction rate of the optimized electrode was about 2.44 times of the 3D Cu foam (15 pieces of Cu foam with the same size as the optimal electrode). Impressively, the catalyst enabled significant alleviation of nitrite because the 3D-PCF substrate could eliminate nitrite rapidly. This work highlights the promise of preparing highly efficient electrocatalyst for efficiently and selectively removing nitrate through supporting of active material onto a 3D monolith substrate.
查看更多>>摘要：In the present approach, the chiral resolution capacity of mixed matrix membranes (MMMs) containing silicon-based mesoporous array (named MCM-41) and grafted with Pirkle-type chiral selector is presented. The mesoporous structure was prepared via the hydrothermal method and the polyethersulfone (PES)-based MMMs were obtained from the phase inversion method. The eco-friendly and sustainable synthesis of the mesoporous architecture from the use of silicon-rich waste proved to be efficient, since the MCM-41 structure exhibited interesting textural and structural features, such as high porosity, large pore volume, uniform pore diameter, and high surface area. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) measurements were useful to confirm the presence of MCM-41-Pirkle within the MMMs. The performance of the MMMs was evaluated through filtration tests with the analyte 2,2,2-trifluoro-l-(9-anthryl) ethanol (Pirkle's alcohol). The concentration of both enantiomers throughout the filtration was monitored by liquid chromatography (LC) using L-phenylglycine column Regis? Technologies (25 cm, 4.6 mm d.i., 5 |im). The MCM-41-Pirkle incorporated within the PES matrix exhibited a good enantioselectivity (a = 1.28) and 45% of the (R)-Pirkle's alcohol was retained. According to our findings, this nano-architectured material can be considered a relevant alternative with great potential for chiral separations in polymeric membrane technology.
查看更多>>摘要：The frequent oil spill accidents and a large amount of industrial oil wastewater discharges had caused serious economic losses and damage to the marine ecological environment. Hence, oil-water separation technology had received increasing attention from researchers. Herein, three-dimensional (3D) nickel sponge was prepared via a facile hydrothermal reduction route. The nano-spines structure of nickel sponge could exhibit superhydrophobic/superlipophilic properties without further hydrophobic modification by low-surface-energy chemicals. Due to the opened hierarchical porous structures and higher porosity, nickel sponges have excellent adsorption capacity for various oils and organic solvents. Nickel sponge has good resistance to ultraviolet rathation, corrosive aqueous solution ability, can be used for long-term outdoor applications. Moreover, the nickel sponge can also selectively absorb oil from oil/water mixtures under turbulent flow conditions. In addition, nickel sponges can continuously and rapidly collect oil from immiscible oil/water mixtures with the aid of a vacuum. Nickel sponge can also efficient selective filter oil/water mixture with a high separation efficiency over 97%. Due to the combination of metallic properties and the low density, nickel sponges are expected to have potential applications in oil absorption, flexible electrodes and industrial catalysis.
查看更多>>摘要：A commercial ZrO2/a-Ai2O3 ceramic ultrafiltration (UF) membrane system with a capacity of 24 m h~ and cut off of 20 kDa was used to treat cold-rolling emulsion wastewater (CREW) from an iron and steel industry in Central China. The ceramic membrane exhibited high removal efficiency for oil and chemical oxygen demand (COD), with an average removal rate of 99.88% and 98.41%, respectively, which were better than other reported state-of-the-art ceramic membranes. In order to solve the problems of membrane fouling and low permeation flux in the treatment of CREW, the control strategies were proposed. The results showed that the membrane fouling can be mitigated by controlling the feed concentration in circulation tank, increasing the cross-flow velocity, and proper chemical cleaning. The membrane fouling mechanism revealed that the experimental data were well described by the combined model of cake filtration and pore blocking at low cross-flow velocity (4.0-4.3 m s~ ). At high cross-flow velocity (5.2 m s~ ), the pore blocking models fit the data well. After optimizing the process operation parameters, the continuous operation time of the UF membrane was prolonged by 1.5-2 times, the cleaning times were reduced by 40%. The total operating cost of this system is about $3.01/m , which is cheaper than the conventional treatment process. In addition, the service life of the ceramic membrane tube was greatly extended to more than 8 years, thus saving the cost of replacement. These results indicate that the process is an economical and efficient method in the treatment of CREW.
查看更多>>摘要：Drived by high concentration difference between the dilute chamber and the concentrated chamber, the reverse permeation of acid ions and water seriously weakens the concentration effect of the targeted acids separated from acidic effluents through the electrodialysis process. Based on rational structure optimization of ion exchange membranes, we propose the TWEDMS membrane modules consisting of the compact ion exchange membranes, compared with the TWEDM membrane modules consisting of the loose ion exchange membranes for the recovery of HCl, HNO3, H2SO4 and H3PO4. Due to suppressing the reverse permeation of acid ions and water from the compact membrane structure, the TWEDMS membrane modules can provide higher concentration differences and current efficiencies for the recovery of HCl (2.177 mol L~(-1) and 39.07%), HNO3 (1.928 mol L~(-1) and 19.68%) and H2SO4 (1.532 mol L~(-1) and 40.60%) at 180,160 and 220 min respectively, reflecting superior separation effects of inorganic acids from acidic effluents. Among the recovery of these inorganic acids by the TWEDMS membrane modules, the recovery of HCl shows the largest concentration difference (2.032 mol L~ ) at 160 min in the electrodialysis process, while the recovery of H3PO4 provides the highest current efficiency (48.67%). According to the analysis of electrical energy consumption, the membrane resistance and water permeability coefficient can play an important role in the reduction of electrical energy consumption (for example, from 17.53% of TWEDMS to 15.08% of TWEDM for HCl at 180 min) for the recovery of inorganic acids from acidic effluents.
查看更多>>摘要：Air pollution has steadily worsened in recent years, and the coronavirus disease 2019 has been spreading since 2020. The electrospun fbrous flters present superior fltration performance, while the low mechanical property and yield of them limit their applications, which must be addressed urgently. Herein, polyacrylonitrile (PAN) sub-micron fbrous membrane with hierarchical structure was easily manufactured using free surface electro-spinning in mass production for air purifcation. The “sandwich” structured fbrous flter was thermally bonded with bi-component nonwoven through traditional bonding procedures, due to melting and bonding of the cortex of bi-component fbers, in which the electrospun fbrous web as the mid layer with tortuous channels showed superior fltration performance for aerosol particles with diameter of 260 nm, which could effectively intercept different-sized particles suspended in the air. In addition, the impact of the processing parameters on the characteristics and fltration mechanisms of thermally bonded composite materials was thoroughly investigated. The results showed that composite material with “dendrites” and “axon” morphologies presented the best formability, outstanding peeling strength and breaking strength, and steady fltration performance, following an easy through-air bonding procedure, making it useful for post-processing in air purifcation. The reinforced composite flter, which is thermally bonded with sub-micron fbers with high yield and nonwoven, is save-energy and has a low operation cost, indicating its promising commercial possibilities.
查看更多>>摘要：Recycling water and waste heat from wet flue gas is crucial for sustainable energy-water-environment nexus in industrial processes. Herein, we report the use of wire-wrapped and helically-finned tubular ceramic membranes to construct membrane condensers for simultaneous water and heat recovery. Compared with conventional plain tubular ceramic membrane (PTCM), wire-wrapped tubular ceramic membrane (WTCM) and helically-finned tubular ceramic membrane (FTCM) both exhibit superior water and heat recovery performance, indicating a non-negligible effect of chaotic fluid mixing on heat and mass transfer enhancement. FTCM shows better condensate capture performance than WTCM. Moreover, improved condensing heat transfer performances are observed on FTCMs provided with large fin height and pitch. FTCM provides higher heat transfer coefficients than PTCM at around 7.4% to 59.3% depending on different fin structures. Effects of operation parameters on membrane condensation process using FTCM are also investigated. Gas-side parameters have significant effects on water/heat recovery performance than water-side parameters. This study can serve as a basis for process intensification of membrane-based condensation used for flue gas dehumidification.
查看更多>>摘要：Nitrogen-polluted wastewater posed great threat to the environment and human beings. Bismuth-based materials have presented high potentials for wastewater treatment. However, it suffers from unsatisfactory electrocatalytic efficiency, especially for nitrate-N removal. Considering the superior performance of copper in electrochemical reduction reactions, Cu2O nanoparticles modified BiO_(2-X) nanosheets (Cu2O NPs/BiO_(2-x) NSs) were designed and synthesized through a one-step hydrothermal method for wastewater purification. The obtained Cu2O NPs/BiO_(2-x) NSs presents enhanced electrocatalytic activity towards nitrate removing, since the introduced CU2O NPs not only increased the active sites but also decreased the electrical resistance. The effect of reaction parameters (current density, initial concentration, initial pH, supporting electrolyte, and dissolved oxygen) was also studied to optimize the operation conditions. Meanwhile, the electrochemical and scavenging experiments illustrated the mechanism that both the direct electron transfer and atomic H played important roles in nitrate reduction. Furthermore, when applying Cu2O NPs/Bi02-x NSs for the treatment of nitrobenzene (NB), it achieved nearly 90% removal efficiency of NB in 30 rain. Therefore, the designed CU2O NPs/BiO_(2-x) NSs shows a wide range of potential for removing both nitroaromatic and inorganic nitrogen pollutants.
查看更多>>摘要：The degradation of carbamazepine (CBZ) by activated peroxymonosulfate (PMS) using the (3R + 2H)-CuFeO2 nanocomposite photocatalyst was investigated in this work. The (3R + 2H)-CuFeO2 were prepared by hydrothermal method at 160°for 15 h utilizing ferrous sulphate heptahydrate (FeSO4-7H2O) and copper (II) sulphate (CuSO4-5H2O) as raw materials. Meanwhile, the (3R + 2H)-CuFeO2 was characterized and analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), isothermal nitrogen adsorption (BET), and X-ray energy spectroscopy (EDS). The best removal effectiveness was 85.96% when critical factors such as the starting pH value, catalyst dosage, and PMS quantity were turned. The action of anions was then investigated further. The high catalytic efficiency was due to the synergistic impact of Fe~(3+)/Fe~(2+) and Cu~(2+)/Cu+ redox cycles. The plausible CAZ breakdown routes were postulated based on the results of the liquid chromatograph-mass spectrometer (LC-MS). Finally, we have studied the most probable of cation migration by the 3DBVSMAPPER program and BVEL calculation concept to correlate the structural characteristics of both materials and their ionic conductivity. The formed channel shows the uniform transport of ions, which can optimize the solid-liquid interface, hinder the influence of water molecules on the material, and protect the material.
Nurul Umairah M. NizamMarlia M. HanafiahEbrahim Mahmoudi
13页
查看更多>>摘要：Graphene oxide (GO) has excellent adsorption capacity as a promising adsorbent due to its large surface area consisting of large number of oxygen-functional groups. Nonetheless, the properties of GO are heavily influenced by the graphite sources and the type of pretreatment. This study aims to investigate the effect of pre-treatment of graphite sourced from agricultural wastes on the properties of the GO for the adsorption of dyes and heavy metal ion. Two sources of graphite (pre-treated with NaOH and H2SO4) were synthesised using biomass wastes (rubber seed shells) and were utlilized to produce high-efficiency GO for the adsorption of Methylene blue (MB), Congo red (CR) and Cadmium (II) from aqueous solutions. The effect of pre-treatment on the GO properties, behavior and performance was evaluated through batch adsorption studies which were conducted under operational condition of activation temperature (25-55 °C), contact time (2-20 min), dosage (0.02-0.1 g), pH (2-12) using impregnation ratio of 1:4. The morphological analysis revealed that GO pretreated with NaOH (GO-N) graphite source exhibited more porous surface area compared to GO pretreated with H2SO4 (GO-H) graphite source, the surface properties was attributed to higher oxygen ratio as indicated in the EDX mapping and as demonstrated in the BET analysis. In general, both GO demonstrated excellent adsorption capacity due to their single-layered planes with noticeable functional groups which included hydroxyl, alkoxy, and carboxyl groups along with the u-n interactions and hydrogen bonds. Maximum monolayer adsorption capacities for the effective removal of CR, MB and Cd (II) was achieved as 299.38, 311.54, and 107.65 mg g~(-1) respectively onto GO-N compared to GO-H as illustrated by the Langmuir isotherms. Furthermore, the results showed that the experimental data were well-fitted to the pseudo-second-order model for both CR and MB including Cd (II) with GO-N with higher correlation coeficient R2 (R2 > 0.9) recorded. Thermodynamic study signified that the enthalpy (AH) and Gibbs free energy (AG) values of the adsorption process for both pollutants were negative indicating that adsorption of CR, MB and Cd were spontaneous and exothermic in nature which suggests that the adsorption of dyes and heavy metal from an aqueous solution was attributed to the presence of active sites and functional groups on the GO surface. However, the study revealed that GO-N proved to be a better adsorbent compared to GO-H under same operational condition and can be considered as a promising and cost-effective adsorbent for the removal of dyes and metal ions from industrial wastewater.
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