جستجوی مقالات مرتبط با کلیدواژه "advanced oxidation" در نشریات گروه "محیط زیست"

Industrial wastewater treatment is more difficult than urban sewage due to the presence of various pollutants. Sewage produced in the leather industry should be treated to the environment due to having a pollution load and the presence of high chloride ion before discharge. The advanced oxidation process based on dioxy persulfate is considered a new process in the presence of active agents. This process has a great capability in wastewater treatment with high pollution. In this study, the anion process of persulfate was used with the activation of magnetic iron (Fe3O4) and zero-valent iron at laboratory scale in order to treat and reduce the organic load (COD) waste water of leather industry.

In this process, the effect of primary pH variables of wastewater (5-9), reaction time (0-60 minutes), Anion concentration of persulfate (50-200 mg per liter) and the amount of iron-containing nanoparticles (0.5-2 grams per liter) were investigated.

The best conditions of the advanced oxidation process in the presence of zero-valent iron include pH 3 ،The amount of magnetic iron nanoparticles was equal to one gram per liter and the amount of dioxy persulfate was equal to 100 mg per liter. During the mentioned conditions, the efficiency of the process was achieved by 85 percent. The findings revealed that the initial COD (COD process reduced 3,700 milligrams per liter to below 1,000 milligrams per liter COD final to 555 milligrams per liter.

Advanced oxidation process based on dioxy persulfate in the presence of iron compounds (zero-valent iron and magnetic iron) due to high performance (removal of 85 percent of primary COD and reduction to 555 milligrams per liter, can be used for decomposition and mineralization of pollutants, pollutants, water, especially industrial sewage. The effluent from this system can be drained into municipal wastewater treatment plants, so by reducing COD to 555 mg per liter, it still cannot be used alone.

The advanced oxidation process using zero-valent iron particles and radicals activated by ultraviolet sulfate to remove phenol from synthetic wastewater is known as a highly efficient method. The aim of this study was to investigate the pH and kintic changes in ZVI/PS/UV process for the removal of phenol from wastewater. Each experiment was performed in a Plexiglas reactor equipped with 2 sources of ultraviolet radiation (254 nm). The characterization of zero valent iron was determined by XRD, SEM, EDAS, and BET analyzes. The results showed that the specific surface area of ​​zero valent iron was 4.43 m2/g. The average size of iron nanoparticles was 35.48 nm. SEM analysis showed that the crystals had a suitable crystalline structure. The adsorption results showed that at an initial pH of 6, the highest phenol removal rate of 94.87%±3.85 was obtained. The kinetic study showed that the ZVI/PS/UV process for phenol removal follows  second order and pH is effective in removing phenol from wastewater.

Denitrification of drinking water has a research history of more than three decades in the field of water treatment and is still the subject of many research projects. The main purpose of this study is to obtain or modify methods for removing nitrate from drinking water in an economic way and force minimal adverse effects on the environment. The use of photocatalytic process for denitrification is not new, but there are still many ambiguities. In this study, the feasibility of using two different photocatalysts over the ultra-high performance concrete (UHPC) substrate was discussed. This new substrate is fabricated by immobilizing the photocatalyst inside a cement matrix which acts as an active layer over the UHPC surface. Optimum long-term lifecycle and higher efficiency of this active surface is achieved without a significant drop of the photocatalyst activity near the surface. In this study, the possibility of using photocatalytic composite layers over the elements made of UHPC for applications such as water supply channels was evaluated and the challenges of using such layers on UHPC surfaces were described. According to the studies, it was found that the use of fixed cement composite bed for photocatalytic treatment has advantages over other methods of photocatalytic water treatment.

In this study, the treatability of pulp and paper wastewater has been studied using a combined method (ultrafiltration and fenton) in a laboratory scale. First, the effect of membrane filtration on the removal of turbidity and COD, as well as membrane flux and membrane fouling were investigated, and then the advanced oxidation method was used to supplement the treatment and increase the removal efficiency of the pollutants. At the end of the membrane filtration operation, the removal efficiency of turbidity was 99%. Based on the results, the average COD of the filtration process with 41.8% removal efficiency was 906 mg/ l. Under optimal pressure conditions bar-1, the amount of membrane flux in the first backwash was equal to 1/99 L.m-2.h-1 which this amount reached to 1/26 L.m-2.h-1after the fourth backwash. the Fenton process removed 862/5 mg /L COD from the pretreated wastewater by UF membrane with an optimal dose of 1.5 mM for Fe +2 and 6 mM for a hydrogen peroxide at an initial pH of 3 and at a 17minute reaction time .In these conditions, the removal efficiency of COD, BOD5 and color was 95%, 90.3% and 92.1% respectively, These results shows high efficiency of the advanced oxidation process to remove contaminants in pulp and paper wastewater

Due to increase of water consumption and lack of resources, wastewater reuse, especially in the industries, as one of the methods for supplying water needs is considered. Dyeing industries are among the large consumers of water and the major problem of their produced wastewater is that it contains color materials and it is non-biodegradable. The conventional methods for removing color from wastewater often lead to production of a large amount of sludge, posing the problems of sludge disposal and treatment. Electro-Fenton process is an advanced oxidation process which can decrease the pollutants organic and color concentrations effectivelly.

In this method, sampling of wastewater was done according to standard methods book for the examination of water and wastewater principles. Then the samples were transferred to the made electrochemical cell pilot, and the impact of various parameters including the amount of electric current, rate of consumption of iron ions, pH and electrolysis time on operating conditions of process was evaluated.

The results showed that under the optimal conditions as current intensity of 20 V for color concentration of 100 mg/L and current intensity of 30 V for color concentration of over 200 mg/L time range of45-60 min, iron ion oncentration of 0.3 mg/L and pH = 4, color removal of 100% can be achieved.

Electro-Fenton process is capable of removing Reactive Blue19 dye with different concentrations and maximum efficiency. Based on the results obtained, it was found that the electric current intensity and iron ion concentration are the parameters affecting the Electro-Fenton process for the removal Reactive Blue19 dye, whereas electrolysis time and pH parameters were less effective on the efficiency of Electro-Fenton process for the removal of Reactive Blue19 dye