Organic Pollutants In Industrial Wastewater Research Articles

Removal of organic pollutants in industrial wastewater with an integrated system of copper electrocoagulation and electrogenerated H2O2

The effectiveness of organics removal of an integrated electrochemical process, namely, electrocoagulation with copper ions followed by the use of electrogenerated hydrogen peroxide was evaluated with an industrial wastewater. The copper (II) ions addition into the wastewater using electro-dissolution of copper electrodes, reduces the chemical oxygen demand (COD) by 56% after 30min of treatment, under optimal conditions of pH 2,8 and 14.2mAcm−2 of current density. The integrated electrochemical process reduces the COD by 78%, BOD5 by 81%, color by 97% and fecal coliforms by 99.9%. The wastewater quality was monitored using UV–Vis spectrometry and Z-potential in order to characterize raw and treated wastewater.

Laccase immobilized onto poly(GMA-MAA) microspheres for p-benzenediol removal from wastewater

Enzymes have already been extensively applied to degrade various organic pollutants in industrial wastewater, and how to improve the stability and reusability of the enzymes is critical to their practical application. In this study, poly(glycidyl methacrylate-methacrylic acid), poly(GMA-MAA), microspheres were prepared by suspension polymerization, and were used as a new support to immobilize Trametes versicolor laccase. The maximum loading capacity to immobilize enzyme reached as high as 44.78 mg protein/g support. The stability and reusability of laccase were greatly improved after immobilization on the microspheres. While the immobilized laccase was used as catalyst to remove p-benzenediol from wastewater, the removal efficiency reached 88.5%.

Efficient adsorptive removal of phenol by a diethylenetriamine-modified hypercrosslinked styrene–divinylbenzene (PS) resin from aqueous solution

Phenol is a typical organic pollutant in industrial wastewater and efficient adsorptive removal of phenol from aqueous solution has attracted many attentions in recent years. In the present study, a diethylenetriamine-modified hypercrosslinked styrene–divinylbenzene (PS) resin, HJ-M05, was synthesized, characterized and evaluated for adsorptive removal of phenol from aqueous solution, and two typical commercial polymeric adsorbents, Amberlite XAD-4 and XAD-7, were employed as references. The equilibrium capacity on HJ-M05 was much larger than those on XAD-4, XAD-7 and the precursor, HJ-55. The degree of the surface energetic heterogeneity of HJ-M05 was proven to be higher than XAD-4 and XAD-7 while the adsorbate–adsorbate interaction of the adsorbed phenol molecules on HJ-M05 was much less than that on XAD-4 and XAD-7. The kinetic data on HJ-M05 could be well plotted by the micropore diffusion model while those on XAD-4 and XAD-7 could not be fitted by this model. Thomas and Yoon models were more suitable for describing the dynamic data than the Clark model and the dynamic capacities on HJ-M05, HJ-55, XAD-4 and XAD-7 were calculated to be 201.7, 178.1, 107.5 and 74.80mg/g dry resin, respectively. 15.0BV (1BV=10ml) 1% of sodium hydroxide could regenerate the HJ-M05 resin column completely and the dynamic desorbed amount was almost equal to the dynamic adsorption amount.

Heterogeneous Catalytic Supercritical Water Oxidation of Refractory Organic Pollutants in Industrial Wastewaters

AbstractCatalytic supercritical water oxidation (CSCWO) is one of the most environmental-friendly advanced oxidation process. It makes a promising technology for the treatment of refractory organic pollutants in industrial wastewaters. Various heterogeneous catalysts including metal oxides have been extensively studied to enhance the efficiency of CSCWO. The present review is concerned about the literatures published in this regard. Phenolics, carboxylic acids and N-containing compounds were taken as model pollutants in most cases, and oxides of Cr, Mn, Co, V, Cu, Zn, Al, Ti and Ce were applied as heterogeneous catalysts. Reports on their characterization and catalytic performances for the CSCWO of aqueous pollutants are reviewed. Discussions are also made on the reaction mechanisms and kinetics proposed for heterogeneous CSCWO.

Dead‐End Liposomal Electro‐Filtration: Phenol Removal by Dioctadecyl Dimethyl Ammonium Chloride as a Case Study

AbstractAmong the important efforts that have been made for the removal of trace organic molecules, sorption by micelles and subsequent membrane filtration is a promising method which, however, still suffers from a number of disadvantages such as low efficiency and high energy consumption. In this article, we present the results of the sorption of phenol (as an important trace organic pollutant in industrial wastewater) to dioctadecyl dimethyl ammonium chloride (DODAC) liposomes, as well as the filtration properties of the resulting dispersion. Whereas the sorption of phenol by a 0.5 wt % DODAC dispersion at neutral pH and ambient temperature was only 26–35 %, it increased to above 95 % at pH 11. Applying an electric field during the filtration process considerably improved both the filtrate flow rate and the retention. An electric field of 5 V/cm increased the filtrate flow rate at 200 kPa 30‐fold.

Build a New Biological Treatment Laboratory System to Reduce Pollution of Some Inorganic and Organic Pollutants in Industrial Wastewater

Build a New Biological Treatment Laboratory System to Reduce Pollution of Some Inorganic and Organic Pollutants in Industrial Wastewater

Model-free control based on reinforcement learning for a wastewater treatment problem

This article presents a proposal, based on the model-free learning control (MFLC) approach, for the control of the advanced oxidation process in wastewater plants. This is prompted by the fact that many organic pollutants in industrial wastewaters are resistant to conventional biological treatments, and the fact that advanced oxidation processes, controlled with learning controllers measuring the oxidation–reduction potential (ORP), give a cost-effective solution. The proposed automation strategy denoted MFLC-MSA is based on the integration of reinforcement learning with multiple step actions. This enables the most adequate control strategy to be learned directly from the process response to selected control inputs. Thus, the proposed methodology is satisfactory for oxidation processes of wastewater treatment plants, where the development of an adequate model for control design is usually too costly. The algorithm proposed has been tested in a lab pilot plant, where phenolic wastewater is oxidized to carboxylic acids and carbon dioxide. The obtained experimental results show that the proposed MFLC-MSA strategy can achieve good performance to guarantee on-specification discharge at maximum degradation rate using readily available measurements such as pH and ORP, inferential measurements of oxidation kinetics and peroxide consumption, respectively.

Benzoate and salicylate degradation by Halomonas campisalis, an alkaliphilic and moderately halophilic microorganism

Alkaliphiles and halophiles have considerable potential to treat organic pollutants in industrial wastewaters having high pH and salinity. As model aromatic compounds, benzoate and salicylate at concentrations up to 380 mg/L were degraded as carbon and energy sources by Halomonas campisalis, an alkaliphile and moderate halophile. Aerobic batch experiments were performed at 50 and 100 g/L NaCl and pH 9. Detected metabolites, catechol and cis, cis-muconate, indicated that H. campisalis used the ortho degradation pathway for both substrates. For benzoate concentrations up to 1600 mg/L, the intermediate 2-hydroxymuconic semialdehyde (2HMSA), characteristic of the meta pathway, was not detected. Improved understanding and characterization of these degradation processes in high pH, high salt systems may lead to improved application of haloalkaliphiles for industrial wastewater treatment.

Ion chromatography–electrospray mass spectrometry for the identification of low-molecular-weight organic acids during the 2,4-dichlorophenol degradation

End-product identification of organic pollutants during oxidation water treatments is of environmental concern due to their potential toxicity. In this work the coupling of ion chromatography (IC), equipped with a membrane ion suppressor, and electrospray ionization mass spectrometry (ESI-MS) has been successfully exploited for the identification of novel low molecular weight organic acids formed as final by-products of 2,4-dichloro-phenol (DCP) degradation by Fenton's reagent, an oxidation method widely employed to degrade recalcitrant organic pollutants in industrial wastewater. The IC–ESI-MS analytical set-up not only allowed the detection of known organic acids but also the identification of 13 new low molecular weight organic acids as a result of extensive oxidation of the parent organic pollutant. Some of the novel organic acids were shown to be chlorine containing by-products and, consequently, of environmental concern. The analytical set-up could be used for characterizing the unknown organic carbon fraction arising from oxidation water treatments.

Chemical vapor deposition of SnO 2 coatings on Ti plates for the preparation of electrocatalytic anodes

SnO 2 coatings have been deposited by metal-organic chemical vapor deposition (MOCVD) on Ti plates using SnEt 4 and O 2 as reactive gas mixture. The thickness, morphology and microstructure of these coatings are controlled by the growth conditions. The deposition process has been used for the preparation of Ti/IrO x /SnO 2 electrodes that were tested for the anodic oxidation of organic pollutants in industrial wastewater. These anodes exhibit a high overpotential for oxygen evolution and a good efficiency for the elimination of total organic carbon (TOC) from wastewater. Electrochemical impedance measurements were used to characterize the activity of the interface SnO 2/aqueous media as a function of time during the oxidation process. The influence of the grain size, thickness and surface pre-treatment of the Ti substrate on the electrocatalytic properties is discussed.