Sustainable integrated process for cogeneration of oxidants for VOCs removal.

This study upgrades the sustainability of environmental electrochemical technologies with a novel approach consisting of the in-situ cogeneration and use of two important oxidants, hydrogen peroxide (HO) and Caro's acid (HSO), manufactured with the same innovative cell. This reactor was equipped with a gas diffusion electrode (GDE) to generate cathodically HO, from oxygen reduction reaction, a boron doped diamond (BDD) electrode to obtain HSO, via anodic oxidation of dilute sulfuric acid, and a proton exchange membrane to separate the anodic and the cathodic compartment, preventing the scavenging effect of the interaction of oxidants. A special design of the inlet helps this cell to reach simultaneous efficiencies as high as 99% for HO formation and 19.

Life cycle inventory for an organic swine waste treatment system.

The aim of this study was to analyze the efficiency of a system of treatment of organic swine waste as a management tool in the transformation of organic waste into products of value in the swine industry. The residues from the pig farm and the products obtained (compost, biol and biogas) were quantified and characterized, as were the energy used within the process and the distribution of the products. The negative impacts on the soil and adjacent river, as well as the efficiency of the compost as fertilizers and biol in grass and corn crops, were evaluated.

New material for arsenic (V) removal based on chitosan supported onto modified polypropylene membrane.

This paper presents a new material easily synthesized and with low cost, with the possibility of remove arsenic and the potential capability for the remediate water bodies. In this work, the efficiency in removing arsenic of the chitosan, supported onto modified polypropylene membrane, was studied using an aqueous As(V) solution of 0.4 mg/L, achieving a removal efficiency of 75%, which corresponds to an adsorption capacity of 0.

Sulfonated and gamma-irradiated waste expanded polystyrene with iron oxide nanoparticles, for removal of indigo carmine dye in textile wastewater.

In this work, waste expanded polystyrene (WEPS) was irradiated with gamma rays, ranging doses from 100 kGy to 1,000 kGy. After irradiation, the WEPS had decrease on its glass transition temperature (Tg), as consequence of the scissions of its polymer chains. Then, the irradiated WEPS was sulfonated, and its degree of sulfonation (DS) was measured.

Effective mercury(II) bioremoval from aqueous solution, and its electrochemical determination.

This work proposed mercury elimination using agricultural waste (Allium Cepa L.). The biomass removed 99.

Reduction of pollutants and disinfection of industrial wastewater by an integrated system of copper electrocoagulation and electrochemically generated hydrogen peroxide.

The objective of this study was to evaluate the effect of copper electrocoagulation and hydrogen peroxide on COD, color, turbidity, and bacterial activity in a mixed industry wastewater. The integrated system of copper electrocoagulation and hydrogen peroxide is effective at reducing the organic and bacterial content of industrial wastewater. The copper electrocoagulation alone reduces COD by 56% in 30 min at pH 2.

Downscaling the chemical oxygen demand test.

The usefulness of the standard chemical oxygen demand (COD) test for water characterization is offset to some extent by its requirement for highly toxic or expensive Cr, Ag, and Hg species. In addition, oxidation of the target samples by chromate requires a 2-3 h heating step. We have downscaled this method to obtain a reduction of up to ca.

Tolerance of Myriophyllum aquaticum to exposure of industrial wastewater pretreatment with electrocoagulation and their efficiency in the removal of pollutants.

The wastewater used in this study was obtained from a treatment plant where it mixed with wastewater of 142 industries and was treated using electrocoagulation with iron electrode and phytoremediation with Myriophyllum aquaticum, likewise certain biomarkers of oxidative stress of the plant were evaluated to find out its resistance to contaminant exposure. Electrocoagulation was performed under optimum operating conditions at pH 8 and with a current density of 45.45 A m(-2) to reduce the COD by 42%, color 89% and turbidity 95%; the electrochemical method produces partial elimination of contaminants, though this was improved using phytoremediation.

Replacing dichromate with hydrogen peroxide in the chemical oxygen demand (COD) test.

The widely used standard method for chemical oxygen demand (COD) involves hazardous chromium species, and its two-hour heating protocol entails a substantial amount of energy expenditure. In the present work we report a proof of concept for a major modification of this method in the range 10-800 mgCOD/L, whereby H2O2 is proposed as a replacement oxidizer. This modification not only reduces the use of unsafe chromium species but also allows for the use of milder conditions that decrease the total energy outlay.

An integrated electrocoagulation-phytoremediation process for the treatment of mixed industrial wastewater.

The elimination of organic contaminants in highly complex wastewater was tested using a combination of the techniques: electrocoagulation with aluminum electrodes and phytoremediation with Myriophyllum aquaticum. Under optimal operating conditions at a pH of 8 and a current density of 45.45 A m(-2), the electrochemical method produces partial elimination of contaminants, which was improved using phytoremediation as a polishing technique.

Enhancing the electrochemical Cr(VI) reduction in aqueous solution.

In this study we present the cathodic Cr(VI) reduction using electrodissolution of iron anode. In batch experiments we tested four different cathodic materials; the best conditions were found when copper was used. It is observed that when more current is applied into the electrochemical cell faster reduction rates are achieved.

Treatment of industrial effluents by a continuous system: electrocoagulation--activated sludge.

A continuous system electrocoagulation--active sludge was designed and built for the treatment of industrial wastewater. The system included an electrochemical reactor with aluminum electrodes, a clarifier and a biological reactor. The electrochemical reactor was tested under different flowrates (50, 100 and 200 mL/min).

Physicochemical and biological combined treatment applied to a food industry wastewater for reuse.

The aim of this study was to improve the wastewater treatment plant (WWTP) efficiency of a food industry. Despite the anaerobic-aerobic treatment, the efficiency of the plant is poor because of the high pollutants load derived mainly from the use of disinfectants and sanitizers. These cleaning products are used in the production process.

Experimental correlation between the pKa value of sulfonphthaleins with the nature of the substituents groups.

This work presents the results obtained from a spectrophotometry study performed on some indicators of the sulfonphtaleins like phenol red (PR), thymol blue (TB), bromothymol blue (BTB), xylenol orange (XO) and methylthymol blue (MTB). During the first stage the acidity constants of some of the indicators were determined using the data from spectrophotometry, potentiometry and with the use of the software SQUAD. These were as follows: for the equilibrium 2H+BTB<-->H(2)BTB, log beta(2)=15.

A combined electrocoagulation-sorption process applied to mixed industrial wastewater.

The removal of organic pollutants from a highly complex industrial wastewater by a aluminium electrocoagulation process coupled with biosorption was evaluated. Under optimal conditions of pH 8 and 45.45 Am(-2) current density, the electrochemical method yields a very effective reduction of all organic pollutants, this reduction was enhanced when the biosorption treatment was applied as a polishing step.