gholamreza moussavi

The air quality index (AQI) does not account the interaction of multiple pollutants, meaning the high concentration and health risk of one pollutant may amplify the effects of others. The main aim of this study was to characterize the ambient air quality of Arak by assessing the combined effects and health risks associated with criteria air pollutants.

This study evaluated the ambient air quality of Arak for the year 1401 on the Persian Calendar, using the concentrations of criteria air pollutants averaged over appropriate timeframes. Additionally, the AQI, aggregate air quality index (AAQI), and health risk-based air quality index (HAQI) were calculated.

Findings showed that the 1-hour concentrations of NO2, SO2, PM10, and PM2.5 exceeded national standards in 0.05%, 0.2%, 12.1%, and 35.5% of hours, respectively. The AQI, AAQI and HAQI values were above 100 in 54.4%, 77.3%, and 56.2% of hours, respectively. PM2.5 was the major pollutant in over 99% of cases.

The results indicated that AAQI and HAQI, in comparison to AQI, characterized the air quality as more polluted. This stricter assessment by AAQI and HAQI may encourage more precautionary measures by authorities and the public. Thus, it is recommended that the decision-makers in Iran’s air quality monitoring in consider adopting these indices.

Vacuum Ultraviolet (VUV)-based advanced oxidation is a new category of advanced purification processes, so this study aimed to compare the efficiency of VUV and Ultraviolet-C (UVC) processes in combination with H2O2 and PMS in degrading Remdesivir.

The photoreactor was investigated with VUV and UVC lamps in combination with H2O2 and PMS for Remdesivir degradation. Also, the effect of variables such as solution pH, H2O2 dose, Remdesivir concentration, the presence of radical scavengers and anions, as well as hydraulic retention time was considered in the continuous process of Remdesivir removal.

The findings showed that the optimal pH in the processes of VUV, UVC, and their derivatives was equal to 7. By adding 1 mM of PMS and H2O2 to the VUV process, the degradation efficiency of Remdesivir was increased from 92.2 ± 0.4% to 98.3 ±2.1% and 100 ± 0.3%, respectively, after 30 min. Also, in the UVC process combined with H2O2 and PMS, the degradation efficiency reached 77.8 ± 1.5 and 85.2 ± 1.3% after 40 min, respectively. The degradation kinetics in the examined processes were as follows: VUV/H2O2 > VUV/PMS > VUV > UVC/H2O2 > UVC/PMS > UVC. The hydroxyl radical was the main reactive oxygen species that led to the decomposition of Remdesivir. The continuous operation of VUV/H2O2 showed that the removal efficiency of Remdesivir reached 94.7 ±0.8% after 40 min.

Considering the high rate of Remdesivir degradation by adding H2O2, the VUV/H2O2 process can be introduced as an efficient technology for the removal of antiviral drugs.

In some villages of Mazandaran, drinking water may be polluted with various pollutants, especially heavy metals (HMs), due to the shallow depth of drinking water sources and the proximity of these sources to farmlands. Therefore, this study aimed to measure the HM pollution level of drinking water in some villages of Mazandaran province and to assess the attributed health risks.

HMs content of drinking water in 30 villages with separate water sources in Mazandaran province was measured. Concerning the HMs concentration and toxicity, and exposure route through water drinking, carcinogenic and non-carcinogenic risks were assessed using a Monte-Carlo simulation-based method.

The concentration values of arsenic, cadmium, chromium, nickel and lead in water were <1/0-4.26, < 0.05, <0.15-3.74, <0.3-10.89, and <0.8-4.68 µg/L, respectively. The hazard index (HI) values for non-carcinogenic risk due to the exposure to HMs through drinking of water in various age groups ranged from 3.04E-04 to 9.94E-04. Values of cumulative excess lifetime cancer risk (ELCRT) for As and Cr were 9.72E-08 and 6.13E-08, respectively.

The results of this study showed that, fortunately, the concentration of metals in drinking water in the studied area was much lower than the national standards and the attributed health risk. Therefore, the drinking water sources in the studied villages had acceptable quality. However, due to the existence of rice paddies in some villages of Mazandaran province, continuous monitoring of pollution levels in the drinking water sources of these areas is essential.

Among the emerging contaminants, microplastics threaten public health. This study aimed to determine microplastic and mesoplastics in soil of residential areas adjacent to Tehran Landfill and assess its ecological risk.

 The present descriptive cross-sectional study was conducted on 20 shallow and deep soil samples from residential areas near the Tehran landfill in July 2021. The microplastics were floated in NaCl and ZnCl2 solutions, and the mesoplastics were separated manually. The identification of physical and chemical properties of polymers was performed by stereomicroscope and FTIR analysis, respectively.

 The average amount of micro-plastics in shallow and deep soils estimated 76±34.98 and 24.7±19.79 particles/kgsoil, respectively. The average amount of mesoplastics obtained 5.25±2.91 and 3.55±1.09 particles/kgsoil, in shallow and deep soils, respectively. Paired-samples T-test showed significant differences between shallow and deep soil in terms of plastic particles (p<0.001). The most abundant microplastic particles were the fragment-shaped with the particle size of 0.1-0.5 mm and LDPE polymer types with the percentage of 37.75, 44.64, and 46.15, respectively. Mesoplastic particles, the 0.5-1 cm film-shaped particles and LDPE polymer types with the percentage of 62.76, 61.46, and 50.7 were found as the most prevalent. Microplastics and mesoplastics' potential ecological risks value in all sampling points was less than 150, indicating low ecological risk.

 Despite the low PERI of microplastics and soil mesoplastics in residential areas, the Eri index for LDPE was high. Thus, Ecological risk is probable if control measures are not taken against plastic pollution.

Imidacloprid, a neonicotinide plant toxin, is used as an insecticide in agriculture. Due to its high degradation resistance and water solubility it is of highly concerns. Therefore, the aim of this study was to investigate the degradation of imidacloprid by modified magnesium oxide catalyst under irradiation of light and peroxymonosulfate.

In this study, modification of magnesium oxide with nitrogen was made by sol-gel method and then iron oxide nanoparticles was used as a magnetic source. Operational parameters were catalyst loading, peroxymonosulfate concentration, reaction time and common anions (nitrate, bicarbonate and chloride). Residual concentration of contaminant was measured by high performance liquid chromatography (HPLC) and mineralization rate was evaluated by measuring TOC.

The results of the study showed that the photocatalytic degradation of the pollutant in the optimal condition was as following: catalyst concentration= 150 mg/L, peroxymonosulfate = 75 mg/L and reaction time= 60 min was 88%. Moreover, at optimum condition, the rate of mineralization was obtained 52%. Results comparison for prepared catalyst under light and dark condition indicated that the as-made catalyst is photocatalytic.

The as-prepared catalyst can be activated as a photocatalyst under LED light and proxymonosulfate for removal of organic pollutants.

Vegetables are one of the most critical groups in people's diet, and quality assurance plays a significant role in health and food safety. Consumption of vegetables is one of the main exposure routes for heavy metals. This study aimed to assess the carcinogenic and non-carcinogenic risks of vegetables cultivated around the Tehran landfill areas in 2019.

This descriptive study was conducted using available sampling method in 2019 on eight types of vegetables. The concentrations of heavy metals were measured using ICP-OES after acidic digestion. The carcinogenic and non-carcinogenic risks were calculated using the related equations. SPSS software was used to determine the relationships between the variables.

The results showed that the order of heavy metals concentration was Al> Fe> Zn> Mn> Cu> Ni> Pb> As> Cr> Co> Cd. The order of contamination load in different vegetables was lettuce> leek> dill> tomato> eggplant> potato> onion> cabbage. Pearson coefficient correlation showed a very strong significant relationship between Cd with Pb, Mn, and Ni at the level of 1%. Hazard quotient (HQ) and hazard index (HI) values in all vegetables were below 1, indicating no potential risk for children and adults. Lettuce, leeks, dill, tomatoes, and eggplant and lettuce, dill, and leeks had significant carcinogenic risk for children and adults, respectively.

Considering that long-term consumption of vegetables can expose the consumers to significant carcinogenic risk, mitigation measures and continuous monitoring of heavy metals in crops cultivated in the landfill areas are essential.

Access to safe water is critical for protecting human health. Turbidity is one of the main physical parameters that affect the quality of water from both health and aesthetical points of view. Therefore, waters should be treated based on the standards set for turbidity before consumption. This study was performed to determine the performance of a bench-scale baffled filter system for removing the turbidity, microbial population, and total organic carbon (TOC) from the contaminated water.

  A lab-scale Plexiglas baffled filter consisting of five compartments with a total working volume of 2 L was designed and constructed. The polyurethane foam cubes were used as filter media. The effect of turbidity (10, 50, and 100 NTU) and surface overflow rate (SOR: 7.5, 10 and 15 m/h) was investigated on the performance of the developed system.

A direct relationship between turbidity, TOC, and microbial density was observed in the inlet water. The efficiency of the baffled filter in the removal of turbidity and the period of the filter operation run both enhanced as the SOR was either decreased or the inlet turbidity was increased. In addition, almost complete removal of TOC from the inlet water was noticed.

The results of the present study indicated that the baffled filter system with sponge media can be a novel and effective method for the removal of turbidity, microbial contaminants and TOC from the natural surface water.

 Landfills as municipal solid waste are considered as the source of pollution. The present study aimed to assess the ecological risk of heavy metals in Tehran landfill soil and the adjacent residential area.

 Having consulted with the specialists and considered the waste processing facilities, 12 sampling points were selected and sampled in four seasons. Soil samples were digested using HNO3: HClO4: HCl: HF. The levels of metals were measured using ICP-OES which further applied for the calculation of ecological risk. Kolmogorov-Smirnov, Kruskal-Wallis, and Pearson correlation coefficient analyses were run to determine the significant differences between metals concentrations in various seasons and sampling points. 

 Metal concentration showed to follow theorder: Al > Fe > Mn > Zn > Cr > Pb > Cu >Ni > Co > As > Cd. Kruskal-Wallis results and pairwise comparison showed a statistically significant difference between metal concentrations across sampling points and seasons, especially in rainy seasons. Pearson correlation coefficient displayed a strong relationship between the mean concentrations of Cu - Pb, Cu - Zn, and Pb - Zn with obtained values of 0.932, 0.874, and 0.883, respectively. Cu exhibited the highest contamination factor at the compost and fermentation sites (13.2 and 9.89, respectively). The geo-accumulation index proved the anthropogenic sources of pollution. The potential ecological risk index (ERI) for the sampling sites ranged from 67.3 to 154, with the order of Cd > Cu > Pb > Ni > As > Cr > Zn > Co > Mn. 

 Due to the obtained moderate to severe ecological risk and exceeded background concentrations of heavy metals, it can be concluded that metal changes and soil pollution are both affected by landfill activities.

One of the most important problems facing the water treatment plants is seasonal turbidity removal from the drinking surface waters. In this work, the efficiency of turbidity removal from water surface has been studied using a batch rotary reactor model and electrocoagulation process and different electrodes including iron and aluminum were tested. Finally, the optimum values of the studied parameters were evaluated at different operating conditions.

In order to eliminate the turbidity from drinking water, the discontinuous rotary reactor model with monopolar electrodes was used in parallel connection. The sample volume in the experiments was 377 liters, and the rotation of the model caused all fluid particles, sediments, and contaminants to be homogeneously touched with the electrodes. This model provided a higher efficiency of turbidity removal due to not having pump blades and return pipes.

Results of this study showed that the maximum efficiency of turbidity removal from drinking water would be achieved by using the material of aluminum for electrode and considering time duration of 60 min,  rotation speed of the model equal to 1.3 rpm, current density of 18.8 A/m2 in pH=7.4 and electrode gap distance of 3 cm. At these conditions the maximum turbidity removal efficiency was obtained 84.1 and 93.3% for the iron and aluminum electrodes, respectively.

Results of this work showed that the proposed batch rotary reactor model, in addition to its easy application, is able to remove turbidity from the aqueous solutions at a the high efficiency. Therefore this model would be strongly suggested for application in drinking water treatment plants.

Herbicides, including atrazine, are among the most important newly discovered contaminants found in water bodies and are hazardous to human health and the environment. adsorption is one of the best techniques used to remove these contaminants from  contaminated water.

In this study, two carbon from waste Pomegranate and  calligonum Comosum were used to remove atrazine herbicide. After chemical activation these carbons with NH4Cl, and then 800 ° C for 2 hours, parametric tests were performed and the effect of pH, adsorbent concentration, atrazine concentration and contact time were investigated; then absorption equilibrium tests; absorption capacity and its isotherms  investigated for the removal of atrazine by two carbons were calculated.

The results showed that the carbon produced from the calligonum Comosum wood in optimal conditions at pH =7; carbon concentration 0.2 g/L, and the mixing time of 50 minutes could remove 100% atrazine at 25 mg/L . The carbon produced from pomegranate in optimal conditions pH =6; carbon concentration of 0.2 g/L and mixing time of 50 minutes could remove 91.5% atrazine to 25 mg/ L. Absorption equilibrium tests showed that the absorption capacity of carbon Calligonum Comosum and  pomegranate were 672 and 645mg/g respectively. Discussion The results of this study showed that both carbons have high absorption capacity in the removal of atrazine herbicide and can be an effective and economical absorbent for the removal of this contaminant from natural waters.

Toluene is one of the volatile organic compounds and used extensively in industrial processes. Because of toluene effects on human health and environment, it is necessary to implement methods for toluene removal from contaminated air stream. Catalytic ozonation process (COP) is one of the emergent technologies for removal of volatile compounds from air streams. Catalytic ozonation process is an efficient, cost-effective and easy to operate for elimination of organic compounds. One of the main factors directly affecting the VOC removal efficiency and ozone destruction rate is the type of catalyst. In this study the potential of MnO/GAC and MgO/GAC catalysts was investigated for toluene elimination from air stream in the presence of ozone in a lab scale.
The MnO/GAC and MgO/GAC catalysts were prepared by Sol-gel method and then characterized by BET, XRD and SEM analysis. Specific concentrations of toluene in the air were produced by using an air pump and a syringe pump. Phocheck was used to measure the concentration of toluene in gas phase. The effect of retention time (0.5-4 Sec), inlet toluene concentration (100-400 ppmv) and air temperature (25-100˚C) were investigated on catalysts efficiency in the presence of ozone. Ozone dosage (0.1 g/h) kept constant in all experiments. The efficiency of MnO/GAC and MgO/GAC were determined from the breakthrough time and removal capacity and the results were compared statistically.
The BET surface area derived from N2 adsorption- desorption isotherms. From the results the BET surface area of MnO/GAC (1103 m2/g) was greater than that of MgO/GAC catalyst (1082 m2/g). XRD patterns clearly illustrate formation of MgO and MnO crystals on GAC surface. From XRD patterns the peaks at 2θ degrees of 50.3° and 73.8° were related to the MgO crystals. The peaks at 2θ degrees of 42.1°, 51.8° and 70.9° reveal the formation of Mn3O4. The crystallite phase of MgO and MnO was hexagonal and tetragonal respectively. The average size of MgO and MnO crystals was 10 and 12 nm, respectively, calculated using Debby-Scherrer equation. Results of experiments in different retention times showed that breakthrough time of MnO/GAC and MgO/GAC catalysts increased 11.3 and 13.9 times, respectively, by increasing retention time from 0.5 to 4 Sec. When inlet toluene concentration increased from 100 to 400 ppmv, the breakthrough time of MgO/GAC and MnO/GAC columns decreased 65% and 62.2%, respectively. In contrast, removal capacity of MgO/GAC and MnO/GAC was increased 39.1% and 50.4% by increasing inlet toluene concentration from 100 to 400 ppmv, respectively. The efficiency of MgO/GAC and MnO/GAC catalysts was increased 78.3% and 31.5% by increasing air temperature from 25 to 100 ˚C, respectively. These results demonstrates that increase of retention time and bed temperature could positively effect on the performance of MgO/GAC and MnO/GAC catalysts in toluene removal from waste air stream in the presence of ozone.
It can be concluded that MgO/GAC and MnO/GAC catalysts had high potential in VOCs removal from air stream in the presence of ozone. The difference between the efficiency of MgO/GAC and MnO/GAC catalysts was significant (P ≤ 0.05) and MgO/GAC catalyst had higher efficiency than MnO/GAC for toluene removal from waste air in the presence of ozone.

The vacuum UV (VUV) system is a novel chemical-less advanced oxidation processes (AOP) used to decompose different class of organic contaminants. The present study aimed at investigating the efficiency of VUV process to degrade toluene as a model of aromatic hydrocarbons from the gas stream in a bench-scale photo-reactor.
The effect of various parameters including radiation flux, relative humidity, toluene concentration, and ozone dosage were investigated on toluene degradation in the VUV process.
The results showed that increasing the relative humidity up to 45% could considerably accelerate the oxidation of toluene as compared with the dry air stream in the process. Complete destruction of toluene was reached at radiation fluxes of 0.366 and 0.732 mJ/cm2 for 5 and 15 ppm of toluene, respectively. Dosing ozone into the VUV photo-reactor at the dosages of 20, 40 and 60 μg/s led to improve the toluene degradation from 65.6% to 100%. The removal of toluene in the VUV process under the selected optimum conditions followed a pseudo-first order reaction model with the degradation rate values of 5.99 mg/L.min.
It was found that VUV process might be a novel and emerging AOP, which can efficiently perform for decomposition of aromatic hydrocarbons in contaminated air stream.

Background Malathion is a pesticide with the highest consumption in phosphoric pesticides. This pesticide has acute and chronic effects. Therefore, for the protection of the water and human health against the harmful effects of these compounds, they must be removed by appropriate treatment of wastewater and water resources. Among the treatment methods, the ozonation process has drawn more attention; one of the best options of ozonation process is the catalytic ozonation process (COP)with activated carbon.
Materials & Methods In this study, at first the synthetic wastewater was prepared at the mentioned concentration with pure malathion. Then, removal malathion experiments in a cylindrical pilot with a total volume of 200 mL were performed by single ozonation and catalytic ozonation process with use of NH4Cl-induced activated carbon (NAC) obtained from of agricultural waste. Study variables included pH, contact time, the concentration of ozone, and the concentration of catalyst. In all conditions, the sole catalytic ozonation adsorption and catalystic synergistic effects were evaluated.
Results The results showed that the removal efficiency of ozone in alkaline pH is higher. Also, in 200 mL samples containing 50 mg/L malathion and 0.1 g/L concentration of catalyst in carbon NAC, in the COP test for 50 minutes, the malathion removal performance was 62.9% in ozonation; 100% in catalytic ozonation, 22% in adsorbtion only, and 15.1% in the synergism effect. It showed the high removal efficiency of COP/NAC.

The efficacy of NH4Cl-induced activated carbon (NAC) was examined in order to adsorb RR198, an azo reactive model dye, from an aqueous solution.
The effects of pH (3 to 10), adsorbent dose (0.1 to 1.2 g/L), dye concentration and contact time on the adsorption efficiency were investigated.
The results showed that the removal of dye was highest at a solution pH of 7 and a powder dose of 1.1 g/L. The 85.9%, 72.6% and 65.4% removal of RR198 was obtained for a concentration of 25, 50 and 100 mg/L, respectively, at a relatively short contact time of 30 minutes, and at optimum pH and NAC concentrations of 1 g/L. The experimental data for kinetic analysis illustrated a best fit to the pseudo-second-order model. The study data on equilibrium were modeled using Langmuir, Freundlich and Dubinin–Radushkevich models; the Langmuir equation provided the best fit for the data.
Therefore, the NAC appears to be an efficient and appropriate adsorbent for the removal of reactive azo dyes from waste streams.

Furfural with a chemical formula of C5H4O2 is a toxic compound which has several health problems for both humans and environment. It has a few exposure routes for entering the human body such as oral, dermal or nasal. In the present study, the efficacies of an integrated catalytic ozonation process (COP) and novel cyclic biological reactor (CBR) were explored for the removal of furfural from aqueous solutions. Activated carbon was purchased from Merck Company. It had a Brunauer, Emmett, and Teller (BET) specific surface area of 1100 m2/g, with an average micropore volume and size of 0.385 cm3/g and 595 µm, respectively. The results indicated that 30% pretreatment with COP could increase furfural and chemical oxygen demand (COD) removal efficiency with CBR 5.56% and 27.01%, respectively. With 70% pretreatment by COP, 98.57% furfural and 95.34% COD removal efficiencies happen in CBR. Generally, batch and continuous experiments showed that the integrated COP/CBR could be efficient in eliminating furfural from wastewater and thus may be a promising technique for treating furfural-containing wastewater.

Nowadays, the reduction of sludge production in the activated sludge process as well as disposal restrictions have drawn much attention. The purpose of this study was to evaluate the feasibility of using ultrasound treatment in increasing the degradation of organic matter in sewage sludge from Shiraz Municipal Wastewater Treatment Plant and also to assess its effect on sludge dewatering. The samples were collected from the anaerobic digester of the Shiraz Wastewater Treatment Plant. The present study was conducted at the bench-scale method. The influence of different pH (3-9) and the effect of contact time (10-120 min) at the constant ultrasonic treatment (37 kHz) on degradation of organic matter were investigated. Since ultrasound is a cyclic sound pressure with a frequency greater than the upper limit of the human hearing range, this limit is approximately 20 kilohertz (20,000 hertz). In addition, the effect of ultrasonic treatment on the total solids (TS), volatile solids (VS), sludge volume index (SVI) and specific resistance to filtration (SRF) were determined. The results of this study showed that the release of soluble chemical oxygen demand (SCOD) in the supernatant and SRF were in the range of 127.9-831 mg/L and 12.48-36.55 m/kg at 10 to 120 min ultrasonic contact time, respectively. In addition, TS and VS decreased from 57.98 and 56.31 to 52.69 and 49.87 mg/L, respectively. Despite the significant reduction in the solids, there was no considerable variation in SVI. This method can be used as a pretreatment method for the treatment of the sewage sludge. Moreover, a complementary treatment is necessary to reach the standard limit.

Electrocoagulation (EC) as an electrochemical method was developed to overcome the drawbacks of conventional decolorization technologies and is an attractive alternative for the treatment of textile dyes. This study was aimed at the optimization of the EC process for decolorization and COD removal of a real textile wastewater using response surface methodology (RSM). RSM is an important branch of experimental design and a critical technology in developing new processes, optimizing their performance, and improving design and formulation of a new products. In this study, a bench scale EC reactor was designed, constructed, and studied for treatment of a textile wastewater. The main operational variables were current intensity, residence time, initial pH, and electrode materials as independent variables; color and COD removal were considered as dependent variables. The experimental runs were designed using selected variables using Design Expert 7.0 software and the process was optimized for decolorization and COD removal using the response surface method. The optimal operational conditions in the EC process for attaining the maximum decolorization and COD removal were current density of 0.97 A, initial pH of 4.04, residence time of 48 min, and Fe electrode. The desirability factor for Fe electrode was 1, while decolorization and COD removal were predicted 76.3 and 75.6% respectively, which was confirmed by the experimental results. The experimental results indicated that the EC process is an efficient and promising process for the decolorization and COD removal of textile effluents. Under the optimized conditions, the experimental values had a good correlation with the predicted ones, indicating suitability of the model and the success of the RSM in optimizing the conditions of EC process in treating the textile wastewater with maximum removals of color and COD under selected conditions of independent variables.

Furfural with a chemical formula of C5H4O2 is a toxic and hazardous substance for human and environment. Furfural and its derivatives such as furfuryl alcohol، alone or in combination with phenol، acetone or urea are used mainly in the production of resin. The second major application of furfural is in the production of solvents such furan and tetrafuran frequently used as a selective solvent in the production، treatment، and refining lubricants from petroleum products. A few studies have recently been done in terms of removal or recovery of furfural. Due to advantages of biological methods، the uses of theses environmentally friendly methods are being investigated in this study. We used cyclic biological reactor (CBR) and Fusarium culmorum granules to biologically degrade different concentration of furfural and equivalent of COD under different operating conditions. The analysis was based on the measurement of furfural degradation efficiency during operational period using spectrophotometer and measuring influent and effluent COD variations using a closed reflux method. cyclic biological reactor was operated in various flow rate (Q) of furfural-containing wastewater for a different period. For all of the flow rate used، furfural degradation and COD removal efficiency was over 99 and 90 percent respectively. Fusarium culmorum granules were also exposed to different concentrations of furfural at different incubation temperatures showing high furfural removal capacity. Under different operating conditions of biological systems، high removal efficiency of furfural was observed، but CBR in comparison with Fusarium culmorum granules reached the optimum and desired removal efficiency in shorter time. Therefore، these systems can be developed and replaced with chemical methods to treat furfural containing wastewater.

Carbon monoxide (CO) is a highly toxic, colorless, and odorless gas with a density close to the air, which is produced by natural processes and anthropogenic sources and is well known for its potential harmful and poisonous effects on humans. Inhalation of carbon monoxide gas can impair the heart and central nervous system. Diatomite supported nano copper oxide catalyst was used to investigate the catalytic oxidation of carbon monoxide. In this study, it was shown that how a low cost diatomaceous earth can be used as catalyst support. The required amount of copper oxide nanoparticles placed into 200 ml deionized water to prepare different concentrations (1wt%, 2wt%, 3wt%, 4 wt% and 5wt%) of nanoparticle, next the suspension liquid stirred for 30 min at pH of 7 at room temperature, and then 100g diatomite was added to the above solution. The nano CuO coating was implemented under sonication conditions in ultra sound bath for 20 min at room temperature, and gently stirring was then carried out for 2h.The prepared catalysts were characterized by Brunauer-Emmett-Teller (BET) surface area, scanning electron microscopy (SEM), X-ray diffraction (XRD) and porosimetry. The influence of reaction temperature, CuO loading, and calcination temperature on the catalytic activity of copper oxide nanoparticle supported on diatomite have been studied. Their catalytic behavior for CO oxidation was studied at different conditions in a tubular reactor packed with catalyst using a multi-component NDIR gas analyzer (Delta 1600 S-IV). The catalytic behavior of catalyst was dependent on the nano copper oxide content, reaction temperature, retention time and the particle size of the catalysts. The results show that diatomite is the promising candidate for catalytic support due to its high surface area, high porosity, low thermal conductivity, very low cost and good sorption ability of its porous media. The catalyst with 4wt % CuO content, in 0.5 l/min and at 400 ºC exhibited the highest catalytic activity. Diatomite, which is a type of widespread natural porous material, provides a suitable support. Chemical and physical characteristics of this support are similar to cordierite. Due to the numerous fine microscopic pores, cavities and channels good sorption ability, chemical inertness, low density, high surface area, unique combination of physical and chemical properties, high permeability and excellent thermal resistance of diatomite, there is a possibility to use it as a support in automotive catalytic converters and as a cost-effective substitute of noble metals for carbon monoxide oxidation. In addition, these unique properties of diatomite can prevent sintering and agglomeration of atoms.

Formaldehyde is a toxic substance and harmful to human beings and the environmental health. Therefore، the effluents containing formaldehyde have to be efficiently treated before discharging into the environment. This study was aimed at investigating the efficiency of Electro-Fenton (EF) Process in pre-treating industrial wastewater containing high concentrations of formaldehyde. The effect of the important operational variables including pH، current density، H2O2 dosage، and reaction time were evaluated on the degradation of 7500 mg/L formaldehyde using batch tests. The EFP batch reactor was consisted of a cylindrical glass column with 5. 20 cm in internal diameter and 34. 50 cm in height. Working volume of the reactor was 500 mL. The maximum formaldehyde removal was obtained at alkaline pH of 10، H2O2 concentration of 10 mM/min، current intensity 8. 5 mA/cm2، and the reaction time of 6 minute. Furthermore، aerating the EFP cell could enhance the formaldehyde removal. Complete removal of formaldehyde was obtained under the abovementioned operational conditions. This study demonstrated that the EFP is capable of reducing high concentration of formaldehyde (7500 mg/l) to the level suitable for biological post-treatment.