Removal of 1,2-dichloroethane from industrial wastewater with membrane filtration

Background and Aims: 1,2-dichloroetane [ethylene dichloride (EDC)] is a chlorinated hydrocarbon which is widely used to produce vinyl chloride. The later is the major precursor to PVC production. Wastewater originating from EDC production is characterized by high turbidity and contains ethylene dichloride and FeCl3 particles. The aim of the present study was to investigate the treatability of EDC effluent using membrane filtration.Materials and Methods: Laboratory scale experiments were carried out on Abadan petrochemical complex wastewater (EDC unit) with various membrane filtration processes that combine microfiltration with nanofiltration. Microfiltration membrane was used as a pretreatment to remove turbidity as well as FeCl3 fine particles, which may subsequently damage nanofiltration system. The microfiltration effluent was thereafter fed to a nanofiltration membrane cell. The filtration performance was assessed through turbidity, TDS, COD and 1,2-dichloroetane removals. pH, temperature and system pressure were also controlled during the study.Results: Successful removal of turbidity (97.5%) and FeCl3 particles (98%) was achieved by microfiltration. EDC concentration in raw effluent was ranged between 2,000 to 3,000 ppm. The nanofiltration membrane cell followed by microfiltration achieved a very high 1,2-dichloroetane removal (96.7) from water. The experimental results indeed showed that the permeate was consisted mainly of water, which asserts that 1,2-dichloroetane was separated in waste phase.Conclusion: The results obtained provide further support for previous researches into this brain area and support the application of membrane technology to remove and recovery of soluble organic compounds from petrochemical wastewater.Key words: Petrochemical wastewater, 1,2-dichloroetane, Membrane filtration, Nanofiltration, Microfiltratio

Sick building syndrome: are we doing enough?

Health and well-being are vitally important aspects of people centric building design and are the roots of productivity. Sick building syndrome (SBS) is a collection of factors that can negatively affect physical health in several ways. Besides physical health is also related to psychological well-being because the human body is one interactive biological system. This paper focuses on reviewing the current state of knowledge on building sickness syndrome which has been prevalent as a building illness since the 1970s especially in offices and schools. While the concepts of intelligent, smart and sustainable buildings have gained considerable attention during recent decades, there is now increasing attention being given to designing healthy buildings. This study provides a review about SBS symptoms. Several negative effects of SBS are identified and potential solutions are advocated. Finally, the study stresses the role of built environment and concludes that ongoing research towards tackling SBS and developing healthy indoor environments should not be limited to a single formula as any health-related building design approach is dependent on several interacting factors

The synthesis and application of the Fe3O4@SiO2 nanoparticles functionalized with 3-aminopropyltriethoxysilane as an efficient sorbent for the adsorption of ethylparaben from wastewater: Synthesis, kinetic, thermodynamic and equilibrium studies

The current study aimed at employing Fe3O4@SiO2 nanoparticles functionalized with NH2 (FSN) to remove Ethylparaben (EtP) from aqueous solutions. A modified co-precipitation method was applied to prepare the nanoadsorbent. The FTIR, XRD, SEM, VSM, and BET techniques were used to determine the structure, particle size, magnetic properties and specific surface area of adsorbent. The performance of FSN in the adsorption of EtP was investigated and removal performance obtained 93 under the selected conditions (pH, 7; adsorbent dosage, 0.4g L-1; EtP concentration, 50mgL-1; and reaction time, 90min). It was found that FSN nanoadsorbent can be used for five cycles with no significant activity loss in the removal of ethylparaben. In order to determine of the adsorption capacity of the adsorbent and to investigate the mechanisms of adsorption, equilibrium data were fitted onto the Freundlich, Temkin, and Langmuir isotherms. The results was showed, the Freundlich isotherm model has the best fit with the experimental data. Furthermore, the kinetic models including pseudo-first-order, pseudo-second-order, intraparticle diffusion and elovich were applied to investigate the reaction pathways and determination of mechanism of sorption reaction. As reported results the best kinetic model was the pseudo-second-order model. Also the thermodynamic studies declared the sorption of EtP onto FSN was endothermic and spontaneous. © 2019 Elsevier Ltd

Degradation of ciprofloxacin by photocatalytic ozonation process under irradiation with UVA: Comparative study, performance and mechanism

The photocatalytic ozonation process (O-3/UVA/TiO2) was applied for the removal of ciprofloxacin antibiotic (CIP) from aqueous solutions. The influence of various operational factors such as solution pH, initial pollutant concentration, catalyst content, ozone dose and scavengers was studied on the process. The mineralization, biodegradability, kinetic models, catalyst recyclability, electrical energy consumption and cost estimation of the process were also performed. Various techniques of FE-SEM, EDS, FTIR, XRD and UV-vis were applied to characterize the catalyst. The highest CIP removal (98.5 ) was obtained in ozone and catalyst doses of 0.34 g/h and 1.0 g/L, respectively during 15 min reaction time at pH 9.0. The scavenging experiments approved the contribution of hydroxyl radicals ((OH)-O-center dot) and superoxide (O-2(center dot-) as the main active radical species in the process. The competition effect of various anions on the process efficiency was in the order of chloride > carbonate > bicarbonate > sulfate. The process kinetics followed the pseudo-first-order model. The catalyst efficiency was about 95 of the original one after 6 recycling steps. It can be concluded that the photocatalytic ozonation process (O-3/UVA/TiO2), due to the low reaction time and high removal efficiency, can be considered as a suitable and practical technique for the removal of antibiotics from aqueous solutions. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved

Performance intensification of BzP photo-catalytic degradation through adding exogenous oxidant

This study was conducted to investigate the photocatalytic removal of Benzylparaben (BzP) using UVC/ZnO (UZ) process in the presence of H2O2 (UZH) from aqueous solutions. The results indicated that mean size and surface area of nano-ZnO were 30 nm and 150 m(2)/g, respectively. The maximum degradation and mineralization of BzP (15 mg L-1) by UZ process under optimum operational conditions (pH: 9.0, catalyst dose: 1 gL(-1) within 90 min reaction), were over 67.37 and 42 of TOC, respectively. The addition of H2O2 (up to 10 mmol L-1) along with UV/ZnO resulted to 100 and 55 removal of BzP and TOC during 25 min of reaction time, respectively. The kinetic studies indicated r(obs) value for UZH process was about 1101.6, 413.12, 367.22, 27.31 and 18.99 times than that of the ZnO, H2O2, UV, UZ and UV/H2O2 (UH), respectively. The values of energy consumption for UV, UZ, UH and UZH were calculated 1280, 95.2, 66.2 and 3.48 kWh m(-3), respectively. BzP was converted to a biodegradable waste after a 90 min and 25 min irradiation time in the UV/ZnO and UV/ZnO/H2O2 processes, respectively

Ultrasound-assisted decomposition of metronidazole by synthesized TiO2/Fe3O4 nanocatalyst: Influencing factors and mechanisms

This study focused on the facile preparation of TiO2/Fe3O4 catalyst prepared by the sol-gel approach as an efficient catalyst for decomposition and mineralization of metronidazole (MTN) in TiO2/Fe3O4/US process. FE-SEM, EDX, VSM, FTIR and XRD analyses were used to characterize the catalyst. The results confirmed the formation of TiO2/Fe3O4 catalyst with the average crystallite size of 32.4 nm. The influence of various factors such as solution pH, catalyst dose, initial MTN concentration and ultrasonic (US) power was examined on MTN decomposition. Also, the effect of various scavengers and inorganic anions was evaluated. In addition, mineralization of MTN, intermediates, reusability and stability tests of catalyst was also investigated. The removal efficiency of MTN by TiO2/Fe3O4 assisted ultrasonic was higher than of pure TiO2 and Fe3O4 nanoparticles. Under the optimal conditions (TiO2/Fe3O4 dosage = 1.0 g L�1, pH = 5.0, initial MTN content = 10 mg L�1, US power = 40 W and time = 90 min), 97.5 of MTN was removed. The scavenging studies expressed that �OH radicals were the main active species in the process. The GC�MS analysis showed that MTN was firstly decomposed into aromatic and aliphatic intermediates in the first stage of the reactions and then mineralized to CO2, H2O and inorganic ions. The removal efficiency of 91.2 for COD and 73.6 for TOC approved the efficient mineralization of MTN solution. The low leakage value of Fe and high reusability of the catalyst (within six consecutive cycles) indicated that TiO2/Fe3O4 had a high stability and reusability and makes it a promising catalyst for efficient degradation of antibiotics in the practical applications. © 202

Optimization of arsenite removal by adsorption onto organically modified montmorillonite clay: Experimental & theoretical approaches

Arsenic is a critical contaminant for aqueous environments as it poses harmful health risks. To meet the stringent regulations regarding the presence of arsenic in aqueous solutions, the feasibility of montmorillonite clay modified with hexadecyltrimethyl ammonium chloride as the adsorbent was tested for the removal of arsenic ions from aqueous solutions. A scanning electron microscopy (SEM) study confirmed that the organically modified nanoclay (ONC) adsorbent had a porous structure with a vast adsorbent surface.The x-ray fluorescence (XRF) analysis proved the presence of carbon in the structure of the modified nanoclay that can be evidence for the creation of ONC. The x-ray diffraction (XRD) analysis results confirm the existence of four main groups of minerals, carbonate (Calcite), clay (Askmtyt and Kandyt), silicate (Quartz), and phyllosilicate (Kaolinite), in the ONC structure.The influence of various parameters such as solution pH, adsorbent dosage, initial arsenite concentration, and contact time on arsenic adsorption onto ONC was investigated. A 2(5) full factorial central composite experimental design was applied. A central composite design under response surface methodology (RSM) was employed to investigate the effects of independent variables on arsenite removal and to determine the optimum condition. The experimental values were in a good fit with the ones predicted by the model. The optimal operating points (adsorbent dosage: 3.7 g L-1, surfactant dosage: 3 g L-1 and the contact time: 37.2min) giving maximum arsenite removal (95.95) were found using Solver "Add-ins" in Microsoft Excel 2010

Application of graphene oxide modified with the phenopyridine and 2-mercaptobenzothiazole for the adsorption of Cr (VI) from wastewater: Optimization, kinetic, thermodynamic and equilibrium studies

In this study response surface methodology (RSM) was discussed as an efficient method for optimization of chromium adsorption onto magnetic graphene oxide(GO-Fe 3 O 4 ) nanocomposites functionalized with two chelating ligands of the phenopyridine (GFP) and 2-mercaptobenzothiazole (GFM). The obtained GFP and GFM nanocomposites characterized using TEM, SEM, FTIR, EDAX, AFM, DLS and TGA. The optimization of adsorption of Cr (VI) onto GFM and GFP was done with the aim of high adsorption performance, minimizing the adsorbent dose and increase of the initial Cr (VI) concentration. Results indicated reduced full second-order (for GFP) and full second-order (for GFM) models were well-fitted with the experimental data. The optimum operating points were achieved (pH, 6.55; adsorbent dosage, 0.098 g L �1 ; contact time, 178.4 min and Cr (VI) concentration, 1 mg L �1 ) and (pH, 6.79; adsorbent dosage, 2.98 g L �1 ; contact time, 118.6 min and Cr (VI) concentration, 4.41 mg L �1 ) for GFP and GFM, respectively. The both adsorbents indicated best fit with Langmuir model. Also, the kinetic models were followed pseudo second order model and pseudo first order model for GFP and GFM, respectively. The thermodynamic studies indicated the sorption of Cr (VI) onto GFP and GFM was endothermic and spontaneous. © 2019 Elsevier B.V

Heterogeneous catalytic degradation of nonylphenol using persulphate activated by natural pyrite: response surface methodology modelling and optimisation

The degradation of nonylphenol polyethoxylates (NPEOs) was investigated by persulphate (PS) activated using naturally pyrite semi-conductor mineral (NP-SCM) in aqueous solutions. The effects of various factors including solution pH, NP-SCM dosage, NPEOs and PS concentration were examined through response surface methodology (RSM) and Box-Behnken design (BBD) technique. The properties of NP-SCM were characterised by FESEM, BET, XRD and EDX analyses. The results showed that the RSM model had a well correlation (R2 > 0.99) between the predicted data and the experimental findings of NPEOs degradation. In addition, under the optimum conditions (PS = 5.85 mM, pH = 3.0, NP-SCM = 0.85 g/L and NPEOs = 10 µM), the removal efficiency of NPEOs reached more than 99. The maximum removal efficiency of COD and TOC was obtained 87 and 80 at 90 min reaction time, respectively. The negative effect of various competing ions on the removal of NPEOs was as phosphate>bicarbonate>copper>nitrate>calcium>ammonium. After five successive catalyst cycles reuse, the degradation efficiency was insignificantly decreased from 99.6 to 90.5, which indicated the excellent potential reusability of NP-SCM catalyst. It can be concluded that NP-SCM along with PS, due to the generation of highly reactive oxidising species (SO4●-), its simplicity and easy separation of the catalyst, has a great potential for the degradation of NPEOs from aqueous solutions. © 2020 Informa UK Limited, trading as Taylor & Francis Group

Enhancing photo-degradation of ciprofloxacin using simultaneous usage of eaq � and radOH over UV/ZnO/I- process: Efficiency, kinetics, pathways, and mechanisms

The aim of this study is to develop the process relies on the UV irradiation of ZnO and I�, i.e. UV/ZnO /I� (UZI), to create both oxidizer and reducer agents simultaneously for photo-degradation of the Ciprofloxacin (CIP). This paper shows that while applying UV irradiation, UV/ZnO and UV/I� for 20 min can lead to achieve 37.5, 58.12, and 61.4 photo-degradation of 100 mg L�1 CIP at pH 7, respectively. Moreover, the UZI treatment can provide 91.54 photo-degradation efficiency. The LC�MS analysis of the UZI effluent indicates that 10 min process was adequate to degrade CIP into simple ring-shaped metabolites while 15 min treatment, mostly of CIP intermediates were linear and biodegradable organic compounds. Furthermore, fourteen little fragments were identified in the CIP photo-degradation via UZI, during the photoreaction time of 2.5 to 20 min. Then, a pseudo first-order kinetics equation was utilized to model the observed photo-degradation process. Finally, the computational results show that the increased concentration of the CIP solution from 100 to 400 mg L�1 decreases the observed rate constant (kobs) from 0.4125 to 0.2189 min�1 while increases the photoreaction rate (robs) from 41.25 to 87.56 mg L�1 min�1. © 2019 Elsevier B.V