ABSTRACT
Background: Natural organic matter is the cause of many problems associated with water treatment such as the presence of disinfection by-products [DBPs] and membrane fouling during water filtration. In this study, the performance of the peroxi-electrocoagulation process PEP] was investigated for the removal of humic acids [HAs] from aqueous solutions
Methods: PEP was carried out for the removal of HA using a plexiglas reactor with a volume of 2 L and fitted with iron electrodes and a direct current supply [DC]. Samples were taken at various amounts of pH [2-4], current density [1 and 2A/cm[2]], hydrogen peroxide [50-150 mg/L] and reaction time [5-20 minutes] and then filtered to remove sludge formed during reaction. Finally, the HA concentration was measured by UV absorbance at 254 nm [UV[254]]
Results: Results indicated that increasing the concentration of H[2]O[2] from 50 to 150 mg/L increased HA removal efficiency from 83% to 94.5%. The highest removal efficiency was observed at pH 3.0; by increasing the pH to the alkaline range, the efficiency of the process was reduced. It was found that HA removal efficiency was high in current density 1A/cm[2]. Increasing current density up to 1 A cm[-2] caused a decrease in removal efficiency. Results of this study showed that under the optimum operating range for the process [[current density] = 1A/cm[2], [hydrogen peroxide concentration] = 150 mg/L, [reaction time]= 20 minutes and [pH]= 3.0], HA removal efficiency reached 98%
Conclusion: It can be concluded that PEP has the potential to be utilized for cost-effective removal of HA from aqueous solutions
ABSTRACT
Sick Building Syndrome has mostly been examined in office environments than in residential spaces. However, in this research, this problem is surveyed in residential buildings of Ekbatan town. Three hundred and thirty cases were, randomly, chosen from among the inhabitants of Ekbatan town. The questionnaires involved questions about the irritative and mental symptoms. A relation was established between the intensification of these symptoms and the physical conditions of buildings e.g. light, ventilation and other factors such as gender and age. Symptoms of Sick Building Syndrome were positive in 56.4 percent of cases. The strongest symptoms observed among the residents include eye irritation during using the computer [8.8%], sore throat [8.5%] and nose irritation [6.4%] near the garbage shooting. The results showed that the residents of buildings without natural sunlight and appropriate central air-conditioning system with [P= 0.04, OR= 1.60] have higher chances of sick building syndrome than residents of buildings exposed to sunlight and good air-conditioning system [with P=0.001, OR=2.41]. The factors influencing the Sick Building Syndrome in this town include inefficient central air-conditioning system, double windows, improper operation and maintenance of shooting system, improper cleaning, and lack of compressor. The neighboring location of Ekbatan town with the polluted areas such as Azadi's West Terminal and Mehr Abad International Airport is among the factors which contribute to the prevalence of the syndrome, as well