查看更多>>摘要：Water pollution caused by pharmaceutical and personal care products(PPCPs)has been significant stress on the water management system.The development of effective and recyclable material for PPCPs removal has become essential.In the present work,a highly efficient g-C3N4/a-Bi2(MoO4)3 nanocomposites was prepared by a simple wet impregnation method and investigated as a catalyst for the photocatalytic degradation of doxycycline under visible light irradiation.The as-prepared catalysts with various mass ratios were systematically characterized with XRD,FT-IR,UV-vis,FE-SEM,EDX,FE-TEM,and XPS.The equal weight ratio(50:50)of g-C3N4/a-Bi2(MoO4)3 nanocomposite exhibits excellent visible light absorption and outstanding doxycycline photodegradation due to the improved separation efficiency of photo-generated charge carriers.After four consecutive cycles,the equal weight ratio(50:50)of g-C3N4/a-Bi2(MoO4)3 nanocomposite shows superior photostability.The scavenger study was carried out to investigate the role of active species in photodegradation activity.More superoxide radicals present on the surface of g-C3N4/α-Bi2(MoO4)3 nanocomposites can significantly enhance the photocatalytic performance.Therefore,a simple wet impregnation method was used to produce a low-cost g-C3N4/a-Bi2(MoO4)3 photocatalyst with the influential effects of removing pharmaceutical contaminants in water bodies.
查看更多>>摘要：Carbon Dioxide(CO2)is the greenhouse gas that most contributes to global warming and climate change due to fossil fuels combustion,transportation,and other industrial process.Carbon capture,storage,and utilization(CCSU)is an effective method to reduce CO2 emission.Chemical absorption is the most straightforward technology for post-combustion CO2,and monoethanolamine(MEA)has been proved to be the most efficient chemical solvent.However,MEA is not environment friend,thus indicating the need for developing eco-friendly absorbers for CO2 capture,such as Deep Eutectic Solvents(DESs).Despite recent experimental studies investigating CO2 solubility in DESs,thermodynamic modelling is important to understand the system behavior.Thus,this study modelled CO2 solubility in thirteen DESs found in a large range of temperature(from 303.15 to 343.15 K)and pressure range(from 0.06 to 12 MPa).Cubic-Plus Association(CPA)and Peng-Robinson 78 equations of state were used to compare efficiency.The results indicate that fitting the binary interaction parameter(k_(ij))promotes a better reproduction result than considering k_(ij)equals zero.Despite all association schemes of CO2 providing accurate results,the 4 C association scheme(two electron acceptors and two electron donors)resulted in better equilibrium description.Both models describe experimental data very well,yet the individual component approach presents better results than pseudo-component approach,corroborating with DESs definition.
查看更多>>摘要：Aerobic granule in continuous-flow process is drawing increasing global interest in a quest for an efficient and innovative technology in the biological wastewater treatment This paper* presents a review of the literature on the development of extended treatments for complicated pollutants,numerous configurations of continuous flow aerobic granular reactors and enhancements of granule stability in long-term operation.The challenges and prospects of full-scale applications of this process were discussed.The review attempted to shed light on our growing knowledge to this technology,which may accelerate the spread of practical applications.
查看更多>>摘要：In this study,a simple method to prepare mixed matrix membranes(MMM)based on Pebax with func-tionalized/oriented graphene oxide(GO)nanosheets is presented to improve CO2/N2 separation.First,the GO nanosheets were surface modified with different amounts of m-phenylenediamine(mPD)to maximize the CO2 adsorption affinity and minimize GO agglomeration within the matrix.Then,an external electric field was applied to organize/orient the GO nanosheets(modified and unmodified)during membrane preparation.The separation performance results showed that the CO2 permeability of unmodified and amine-functionalized GO-filled MMM respectively increased by 1.7 and 2.1 times compared to the neat matrix.This improvement is attributed to the high affinity of amino groups for CO2 uptake.Furthermore,applying a vertical electric field increased the CO2 permeability compared to a random GO orientation state by 1.3 and 2.8 times for the unmodified and modified GO-filled MMM,respectively.This significant improvement is related to a lower tortuosity in the membrane,improving the passage of gas molecules.Overall,the combination of surface treatment(amino group)and orientation(electric field)on GO nanosheets leads to better CO2 permselectivity for the membranes studied.
查看更多>>摘要：The discharge of untreated colored wastewater poses a severe threat to global health.This work reports a simple yet highly efficient way to modify Zhundong coal(MZD)with hydroxyl functional groups for malachite green(MG)removal.The modification significantly improved the adsorption capacity of MG from 63.0 mg/g to 538.7 mg/g.According to Fourier transform infrared spectroscopy,zeta-potential analyzer,X-ray photoelectron spectroscopy,and N2 absorption characterization,the improvement in adsorption capacity was mainly attributed to the enhancement of hydroxyl functional groups on the surface of coal.The adsorption of MG on MZD depended on pH,and the highest removal efficiency reached 99.7% at pH 10 with an initial MG concentration of 500 mg/L The adsorption process was mainly controlled by chemisorption,and it was en-dothermic and spontaneous according to thermodynamic analysis.The adsorption data could be well reproduced by the pseudo-second order kinetic model and the Redlich-Peterson isotherm model.The MZD shows good regeneration performance with only a 16.9% reduction of initial adsorption capacity after five circles.Hydrophobic interactions,π-π interactions,and pore-filling contributed to adsorption,whereas electrostatic interactions played a dominant role in the MG removal by MZD.This work provides a new sight to prepare useful and cheap adsorbents from coal to remove contaminants from printing and dyeing wastewater.
查看更多>>摘要：The combination of ferrate(VI)with hydrogen peroxide(H2O2)was used for the degradation of bisphenol A(BPA)spiked in municipal wastewater reverse osmosis concentrate(ROC).The results showed that the combined Fe(VI)and H2O2 oxidant provided an additive effect to achieve greater degradation efficiencies of BPA in ROC compared to the use of Fe(VI)or H2O2 alone.The degradation efficiency of BPA was studied in detail by assessing the operating conditions,including Fe(VI)dosage,H2O2 dosage,the dosing strategy of Fe(VI)and H2O2,solution pH,and the initial concentration of BPA.It was found that over 99.0% of BPA was degraded(50 μgL~(-1))by using [Fe(VI)]/[H2O2] at a ratio of 1050:5000 and at pH 8.0.In addition,the degradation was also accompanied by 37.2% of dissolved organic carbon(DOC)removal and 94.0% of UV254 reduction.However,when the excess amount of H2O2 was added,it was found that H2O2 started to inhibit the degradation and the degradation efficiency of BPA in ROC lowered.It was also found that the simultaneous addition of Fe(VI)and H2O2 provided satisfactory BPA degradation.Similar degradation efficiency could be achieved by injecting the second oxidant into the system 10 min after adding the first oxidant at time zero.The apparent second-order reaction rate constant(k_(app))obtained was 67.9 × 10~3 M~(-1)s~(-1)at a [Fe(VI)]/[H2O2] ratio of 1050:5000.The overall ecotoxicity of the treated water samples as measured by the Microtox bioassay technique decreased after the Fe(VI)/H2O2 treatment,which indicated that an insignificant amount,if not none,toxic degradation by-products was formed by the oxidative action of the Fe(VI)/H2O2 combined oxidant.The use of Fe(VI)/H2O2 as an alternative treatment option of cost-effectiveness than Fe(VI)alone in water and wastewater industries.
查看更多>>摘要：The current study explored the bioenergy potential of waste miscanthus grass(WMG).The kinetic study of WMG was evaluated via two model-free methods,in a thermogravimetric analyzer(TGA),at dynamic heating rates under an inert ambiance.The pyrolysis was performed in a semi-batch fixed bed reactor at 500 oC,80 oC min heating rate,and 1 mm particle size.The evolution of hot vapours during pyrolysis was explored using a TGA-FTIR analyzer.Finally,the bio-oil and biochar were characterized by their physico-chemical properties.The kinetic results established that WMG followed a multi-step decomposition process,and the average activation energy gained from KAS and ST was found to be 197.66 and 179.64 kJ mol-1,respectively.TGA-FTIR study revealed the foremost release of carbon dioxide(28.22%),followed by a car-bonyl(25.40%),and ether(19.12%).Further,the pyrolysis of WMG yielded 29.32 wt% of bio-oil at the optimized condition whereas,physicochemical results of bio-oil established; 65.16% carbon content,26.16 MJ kg~(-1)HHV,34.15 cP viscosity,and 812 kg m~(-3)density.GC-MS study of bio-oil confirmed the maximal release of hydrocarbons and phenols.Finally,characterization results of miscanthus grass biochar(MGB)demonstrated an excellent feedstock for industrial and domestic applications.
查看更多>>摘要：Resilience is essential to ensure safe and sustainable process operations.It plays a critical role in enabling operations in the remote and extreme environments encountered during operations held of fshore or in the Arctic.Resilience is a property of the process or system,and considers three distinct characteristics: absorption,adaptation,and recovery.This work proposes a resilience assessment framework of process systems with fast responses,such as reaction systems.The three characteristics are modelled using system design variables with covariate consideration.Subsequently,these three characteristics are integrated to assess resilience.To enhance the resilience,design changes and operational interventions are explored.The proposed framework is explained using the assessment of an autocatalytic reactor as a case study.A thermal runaway reaction is modelled for resilience,and operational intervention strategy such as adding inhibition is tested to enhance the resilience of the reactor.It was concluded that as the inhibitor injection time was decreased from 5.8 min to 1 min,the value of the proposed resilience metric increased from 0.7 to 0.9.This case study confirms the applicability and effectiveness of the proposed framework.
查看更多>>摘要：IMO has pushed out strict regulations to limit marine diesel engine emissions.EGR is a mature measure to reduce NOx emissions which would lead PM emissions risen.In this paper,An EGR system combined with a scrubber was built on a marine diesel engine.Based on the experimental platform,the characteristics of PM emissions were studied when the engine burning two kinds of sulfur diesel oils.The results showed that the particle size concentration curves show multimodal distribution and the average particle sizes increased.Most of the PM emissions were distributed in the nuclear mode interval.Moreover,EGR scrubber had a significant effect on removing PM with an efficiency of over 98% and the weighted value of PM emissions was 22.136 mg/kWh,which met China's first and second-stage emission regulations and US EPA Tier 4 emission regulations.
查看更多>>摘要：This study determines the effect of different in situ chemical oxidation(ISCO)technologies on soil microorganisms and total petroleum hydrocarbon(TPH)degradation.Permanganate is a moderate oxidant to the intrinsic microbes while persulfate causes severe bacterial death.TPH removal in the persulfate and permanganate systems is similar,which is higher than that in the hydrogen peroxide system.Permanganate is the most suitable oxidant for ISCO,followed by in situ bioremediation because of its persistence and low toxicity.Chemical oxidation dominates the removal of TPH throughout the experiment in the persulfate systems and during the initial stage in the hydrogen peroxide and permanganate systems.The toxicity of different catalysis/activation methods to in situ microbes decreases in the order: heat> Fe~(2+)/citric acid > Fe~(2+)> no catalysis/activation.If ferrous iron or citric acid is used to catalyze hydrogen peroxide,the pH must be controlled to prevent severe damage to the microbes.There is more dissolved organic carbon in solution in oxidation systems,which shows that the addition of an oxidant increases the solubility and bioavailability of the contaminant.Petroleum degraders are present in the contaminated soil and the addition of oxidants changes indigenous bacterial communities significantly.
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