Assessing the efficiency of Fe:TiO2 nanoparticles in removal of Cat Blue 41 using sunlight irradiation in aqueous media using Response surface method (RSM)

Nowadays, protecting environment, especially aqueous medium is a crucial task in modern world. Because of their nature, dyes have not only negative impacts on the aesthetic aspects of the environment, but also result in serious biological and chemical side effects on the environment. Various processes have been applied for removal of dyes from effluent. The aim of this research was to assess the removal of Cat Blue 41 from aqueous media using Fe:TiO2 in the presence of sunlight. Based on a descriptive-laboratory scale experiment using RSM design experiment, the effect of independent variables of pH, nanoparticles dosage, initial dye concentration, H2O2 concentration and contact time on the photodegradation of the dye was carried out through 26 experimental run. Analysis of the proposed model was performed using ANOVA. The proposed model for the removal of dye was statistically significant at the 95 percent confidence level. The removal efficiency was function of the independent variables of nanoparticles dosage, initial dye concentration, and contact time. The photodegradation of Cat Blue 41 showed high photodegradation efficiency of Fe:TiO2 nanoparticles under sunlight irradiation. It was found that increasing the nanomaterials dosage, contact time, and H2O2 concentration results in increasing removal efficiency so that increasing nanomaterials dosage from 0.3 to 3 g/l resulted in increasing dye removal efficiency from 48.6 to 88.9% respectively. In addition, increasing pH and initial dye concentration led into reducing removal efficiency so that increasing dye concentration from 25 to 200 mg/l resulted in decreasing its removal efficiency from 69.8 to 35.5% respectively. Therefore, design of experiment suitably optimized the removal process and reducing the number of runs resulted in increasing efficiency of the pollutant removal

Assessing biological and chemical indicators of water used in Dialysis Ward of one of the Sanandaj hospitals

The used dialysis liquid is considered as the largest volume of water used in medicine. The concentrated liquid is manufactured in equal commercial quality and fully controlled procedure. But the quality of water used may pose different qualities. Using ordinary tap water to dialysate has always the possibility of transmission of potentially toxic substances from the patient's blood along with it. Therefore, the quality of water used to prepare dialysis solution is of great importance. The aim of this study was to determine microbial and chemical parameters of water used in dialysis center in one of the hospitals in Sanandaj City. This was a cross-sectional descriptive study in which 35 water samples from 10 hemodialysis machine were randomly selected. The study was performed in the second quarter of 2015. The chemical sampling was carried out once per month while the microbial sampling was taken twice per month. Evaluation of chemical and microbial indicators of water used in the dialysis ward of the hospital in Sanandaj showed that the water does not have microbial contamination but exceeding elements such as nitrite, sodium, calcium, and magnesium than the standard in some of the samples make it essential to do further monitoring of the water treated in dialysis ward

Application of response surface methodology for optimization of natural organic matter degradation by UV/H2O2 advanced oxidation process

BACKGROUND: In this research, the removal of natural organic matter from aqueous solutions using advanced oxidation processes (UV/H(2)O(2)) was evaluated. Therefore, the response surface methodology and Box-Behnken design matrix were employed to design the experiments and to determine the optimal conditions. The effects of various parameters such as initial concentration of H(2)O(2) (100–180 mg/L), pH (3–11), time (10–30 min) and initial total organic carbon (TOC) concentration (4–10 mg/L) were studied. RESULTS: Analysis of variance (ANOVA), revealed a good agreement between experimental data and proposed quadratic polynomial model (R(2) = 0.98). Experimental results showed that with increasing H(2)O(2) concentration, time and decreasing in initial TOC concentration, TOC removal efficiency was increased. Neutral and nearly acidic pH values also improved the TOC removal. Accordingly, the TOC removal efficiency of 78.02% in terms of the independent variables including H(2)O(2) concentration (100 mg/L), pH (6.12), time (22.42 min) and initial TOC concentration (4 mg/L) were optimized. Further confirmation tests under optimal conditions showed a 76.50% of TOC removal and confirmed that the model is accordance with the experiments. In addition TOC removal for natural water based on response surface methodology optimum condition was 62.15%. CONCLUSIONS: This study showed that response surface methodology based on Box-Behnken method is a useful tool for optimizing the operating parameters for TOC removal using UV/H(2)O(2) process

Synthesis of immobilised Ni-doped TiO2 nanoparticles through hydrothermal route and their efficiency evaluation in photodegradation of formaldehyde

The aim of the present study was to synthesis Ni-doped TiO2 nanoparticles (NPs) in order to evaluate their effectiveness in photocatalytic degradation of formaldehyde in the aqueous phase. The Ni-doped TiO2 NPs were synthesised using a mild hydrothermal method. They were then immobilized on glass plates by the calcination method. Characterisation of Ni-doped TiO2 NPs was also carried out using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses. The SEM images showed the uniform distribution of assynthesised NPs on the surface of glass plates, with multidimensional crystalline structures. The results indicated that increasing the dopant weight ratio to 0.7% enhanced the photocatalytic degradation efficiency of formaldehyde; however, a further increase in the dopant weight ratio reduced the process efficacy. According to the results, increasing the initial pH from acidic and neutral to alkaline conditions decreased the efficacy of the process. Furthermore, the results showed that increasing the amount of nanocatalyst and decreasing the initial concentration of formaldehyde favoured the photocatalytic degradation of formaldehyde