ABSTRACT
Background and Aim: Widespread use of Chromium and their compounds in many industries, including plating, steel production, and wood protection and tanning leather, can result in the discharge of large amounts of pollutants to receiving waters, leading to toxic effects on human health and the environment. The aim of this study was to determine the efficiency of the photocatalytic process to remove Chromium in the presence of organic matter from the aqueous medium by using nanoparticles of TiO2 synthesized by sol gel
Materials and Methods: This was an experimental study. After nanoparticle synthesis, we used FTIR, SEM, XRD for analysis of nanoparticles. The photocatalytic process for Chromium removal was performed using a discrete stream reactor and Uv light bulb with 30 watts intensity. Then, the effects of independent variables, including pH, concentration of nanoparticles, contact time and the presence of interfering organic matters such as phenol, EDTA, CCl4, methanol and humic acid on the efficiency of the removal of Chromium in an aqueous medium were evaluated
Results: The results showed efficiency of Chromium removal increased after decreasing pH. Also, increasing the concentration of nanoparticles and contact time led to increased removal efficiency. We found reduced removal efficiency after increasing concentrations of the pollutants. Removal efficiency of Chromium increased in the presence of EDTA, but methanol, phenol, humic acid, and carbon tetrachloride reduced its removal efficiency
Conclusion: Photocatalytic oxidation with titanium oxide nanoparticles synthesized by sol- gel method can be an effective way for removal of Chromium from aqueous medium
ABSTRACT
Nowadays, removal of pollutants from water resources is a matter of concern in environmental sciences. Colors in addition to its negative impact on the aesthetic aspects have serious chemical and biological negative effects on the environment. Considering their resistance to heat, light and chemicals, they are not disintegrated easily in the environment. So this type of pollutants must be refined before pouring into the environment. Colors are used in paper, plastics and cosmetic industries and their effluent can contaminate surface and groundwater. The aim of this study was to evaluate the efficiency of modified garlic pods in the removal of cationic blue 41 from aqueous media in batch systems. In this experimental - laboratory study- at first we prepared garlic pods. The optimum pH was determined under stable conditions. Then initial concentration of adsorbent, contact time and different concentrations of dye were assessed at optimal pH level. Using Excel software, data analysis was performed by means of regression coefficient. The results revealed that the maximum cationic dye removal occurred at neutral pH. By increasing the dye concentration elimination of the dye decreased. Also we found that the efficiency of dye removal improved by increasing contact time and adsorbent concentration. Adsorption is a highly efficient method for removal of color, odor, organic and inorganic substances from wastewaters in different industries. Garlic pod is cheap and available and can be used as an adsorbent for removal of dyes from wastewaters in the textile industries
ABSTRACT
Development of manufacturing industries of textile dyes has resulted in marketing new dyes with better dyeing qualities. Improvement of the dye quality is related to the structural stability of the chromogenic materials which make dyes resistant against chemical and biological dissociation. The purpose of this study was to investigate the efficiency of the photochemical processes combined with UV/H2O2 and UV/TiO[2] in removal of Acid Red 18 dye from aqueous solutions in a batch reactor. This study was an experimental-laboratory study. A reactor was designed and fabricated in our laboratory. Then optimum pH was determined in stable condition. The effect of initial concentrations of hydrogen peroxide, titanium dioxide, contact time, and different concentrations of Acid Red 18 dye were systematically assessed while keeping optimum pH constant. Data were analyzed and interpreted using Excel software and regression coefficient. The results of this study revealed increased removal efficiency of Acid Red 18 in acidic pH in the above mentioned processes; however, this efficiency decreased with increased initial concentration of Acid Red 18 dye. Moreover, the removal efficiency of dye increased by increasing contact time and concentrations of hydrogen peroxide and titanium dioxide. In general, our results showed that the photochemical processes combined with UV/H[2]O[2] and UV/TiO[2] could be used as an effective method for removing Acid Red 18 from aqueous solutions. Moreover, comparison of the results indicated that the removal efficiency of the photochemical process combined with UV/H[2]O[2] was higher than that of the photochemical process combined with UV/TiO2. Because of availability, time-effectiveness, and lack of sludge production this process is recommended for removal of Acid Red 18