Ali Jafari

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

BackgroundIn this research, the removal of natural organic matter from aqueous solutions using advanced oxidation processes (UV/H2O2) 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 H2O2 (100–180 mg/L), pH (3–11), time (10–30 min) and initial total organic carbon (TOC) concentration (4–10 mg/L) were studied.ResultsAnalysis of variance (ANOVA), revealed a good agreement between experimental data and proposed quadratic polynomial model (R2 = 0.98). Experimental results showed that with increasing H2O2 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 H2O2 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%.ConclusionsThis 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/H2O2 process.

Heavy metals analysis and quality assessment in drinking water – Khorramabad city, Iran

Continuous monitoring of drinking water quality is essential in terms of heavy metals and toxic substances. The general objective of this study were to determine the concentration of heavy metals in drinking water of Khorramabad city and to determine the water quality indices (The heavy metal pollution index and heavy metal evaluation index). According to the city map, 45 points were selected for drinking water sampling through the city distribution system. The results of this study showed that the average concentration of heavy metals such as Zn, Pb, Cd, Cr, and Cu were 47.01 μg/l, 3.2 μg/l, 0.42 μg/l, 5.08 μg/l, and 6.79 μg/l, respectively. The HPI and HEI (water quality indices) for Zn, Pb, Cd, Cr, and Cu were 46.58, 46.58, respectively. According to the indices, the city drinking water quality is good in terms of heavy metals.

Application of micellar enhanced ultrafiltration (MEUF) for arsenic (v) removal from aqueous solutions and process optimization

ABSTRACT In this study, the removal of arsenic was evaluated using micellar-enhanced ultrafiltration process. Response surface methodology and Box-Behnken matrix methods were also applied to design the experiments and determine the optimum conditions. Therefore, the main operational parameters including pH (4–10), initial concentration of arsenic (20–80 µg/L), and concentration of Cetyltrimethylammonium bromide (CTAB) (1–3 mM) were investigated. The results of analysis of variance revealed a good agreement between experimental data and the built model with the determination coefficient (R2) of 0.99. Accordingly, the removal efficiency obtained was about 94.8% at the optimal condition (pH = 6.73, the initial concentration of arsenic = 29.44 µg/L, and CTAB concentration of 2.83 mM). GRAPHICAL ABSTRACT

Health-risk assessment related to the fluoride, nitrate, and nitrite in the drinking water in the Sanandaj, Kurdistan County, Iran

ABSTRACT The concentration of fluoride and nitrate in groundwater is usually higher than that of surface water. The main objective of this study was to estimate the health-risk assessment associated with fluoride, nitrate, and nitrite in drinking water in Sanandaj and its villages. The number of samples in the Sanandaj and its rural was 106. The average concentration of fluoride in urban and rural drinking water was 0.22 mg/l and 0.27 mg/l, respectively. Fluoride concentration was also close to urban and rural drinking water. The concentration of nitrate in urban and rural drinking water was in the range between 0.28–27.77 mg/l and 1.28–80 mg/l, respectively. The concentration of nitrate reported in rural samples was higher than that of urban samples. The maximum concentration of nitrate reported in this study was 80 mg/l. The mean CDI for nitrate in the men, women, and children was 0.4258, 0.5110, and 1.1454, respectively. The findings of this study indicated that all three groups studied were exposed to nitrate contact hazards (HQ > 1). Therefore, the HQ in each of the three groups was higher than 1, which should be carefully monitored and necessary measures should be performed.

Estimation of health effects (morbidity and mortality) attributed to PM10 and PM2.5 exposure using an Air Quality model in Bukan city, from 2015-2016 exposure using air quality model

Background: Air Quality software is a useful tool for assessing the health risks associated with air pollutants. Quantifying the effects of exposure to air pollutants in terms of public health has become a critical component of policy discussion. The present study purposed to quantify the health effects of particulate matters on mortality and morbidity in a Bukan city hospital from 2015-2016. Methods: Information regarding coordinates, exposed population, number of stations used in profiling, mean and maximum concentrations (annual, winter, and summer), annual 98th percentile, baseline incidence (BI) per 100 000 per year, and relative risk was needed for use with the software. Results: The average particulate matter concentration was higher in summer than in winter. The concentrations of PM10 in summer and winter were 84.37 and 74.86 μg m-3, respectively. The Air Quality model predicted that total mortality rates related to PM10 and PM2.5 were 33.3 and 49.8 deaths, respectively. As a result, 3.79% of the total mortality was due to PM10. In Bukan city, 2.004% of total deaths were due to cardiovascular mortality. The Air Quality model predicted that the deaths of 92.2 people were related to hospital admissions for respiratory disease. Conclusion: The continual evaluation of air quality data is necessary for investigating the effect of pollutants on human health.

The Prevalence of Exfoliation Syndrome in an Iranian Population Aged 45-69 Years.

ABSTRACT Purpose: To determine the prevalence of exfoliation syndrome (XFS) and some of its related factors in an Iranian population aged 45–69 years. Methods: In the first phase of the Shahroud Eye Cohort Study, 5190 people in 300 clusters from Shahroud city in the northeast of Iran participated in the study. The second phase of the study was conducted 5 years later in 2014. Vision testing, refraction, slit lamp examination, and fundus examination were performed for all participants. In this study, XFS was determined by an ophthalmologist using slit lamp biomicroscopy. Results: Of the 5190 first phase study participants, 4737 participated in the second phase (response rate 91.3%). In this study, the prevalence of XFS was 0.46% (95% confidence interval, CI, 0.24–0.68%) and the prevalence of bilateral XFS was 0.20% (95% CI 0.07–0.33%). XFS prevalence in men was 0.74% (95% CI 0.28–1.20%) and in women 0.26% (95% CI 0.07–0.45%). In a multivariable-adjusted logistic regression model, age, sex, diabetes, smoking status, dyslipidemia, and hypertension were entered into the model as covariables, where older age (odds ratio, OR, 1.18, 95% CI 1.08–1.28) was the only variable that remained significantly associated with XFS prevalence. Conclusion: The prevalence of XFS in this study was very low. Similar to other studies, age was a factor associated with this syndrome.

A Detailed and Validated Three Dimensional Dynamic Model of the Patellofemoral Joint

A detailed 3D anatomical model of the patellofemoral joint was developed to study the tracking, force, contact and stability characteristics of the joint. The quadriceps was considered to include six components represented by 15 force vectors. The patellar tendon was modeled using four bundles of viscoelastic tensile elements. Each of the lateral and medial retinaculum was modeled by a three-bundle nonlinear spring. The femur and patella were considered as rigid bodies with their articular cartilage layers represented by an isotropic viscoelastic material. The geometrical and tracking data needed for model simulation, as well as validation of its results, were obtained from an in vivo experiment, involving MR imaging of a normal knee while performing isometric leg press against a constant 140 N force. The model was formulated within the framework of a rigid body spring model and solved using forth-order Runge-Kutta, for knee flexion angles between zero and 50 degrees. Results indicated a good agreement between the model predictions for patellar tracking and the experimental results with RMS deviations of about 2 mm for translations (less than 0.7 mm for patellar mediolateral shift), and 4 degrees for rotations (less than 3 degrees for patellar tilt). The contact pattern predicted by the model was also consistent with the results of the experiment and the literature. The joint contact force increased linearly with progressive knee flexion from 80 N to 210 N. The medial retinaculum experienced a peak force of 18 N at full extension that decreased with knee flexion and disappeared entirely at 20 degrees flexion. Analysis of the patellar time response to the quadriceps contraction suggested that the muscle activation most affected the patellar shift and tilt. These results are consistent with the recent observations in the literature concerning the significance of retinaculum and quadriceps in the patellar stability.

Data on nitrate and nitrate of Taham dam in Zanjan (Iran).

In recent years, contamination of water resources, with pollutants such as nitrate and nitrite, has significantly increased. These compounds can have harmful effects on human health, especially children such as methemoglobinemia. The main objective of this study was to measure the concentration of nitrate and nitrite and its health-risk assessment in the rivers entering Taham dam in Zanjan. USEPA Method was used to assess the health-risk of nitrate and nitrite. According to the obtained results, the concentration of nitrate and nitrite was in the range of 0.51–14.93 mg/l and 0.001–0.061 mg/l, respectively. According to the results, the mean of the CDI for nitrate and nitrite was 9.52*10−2 and 3.63*10−4 mg/kg/day, respectively. Furthermore, the mean HI for nitrate and nitrite was 5.97*10−2 and 3.63*10−3, respectively. The concentration of nitrate and nitrite in rivers was lower than the WHO and Iran guidelines. Based on the results, the HI value in all samples was less than 1 which indicating the non-carcinogenic effects of nitrate and nitrite in these rivers.

Data on the alizarin red S adsorption from aqueous solutions on PAC, treated PAC, and PAC/γ≈Fe2O3

Three types of adsorbents of powdered activated carbon (PAC), treated PAC, and PAC/γ ≈ Fe2O3 nanocomposite were used. The adsorption experiments were performed in batch conditions. pHZPC of PAC/γ ≈ Fe2O3 was 6.7. As a result, at lower than pHZPC, acidic pH, the adsorption of alizarin red S on PAC/γ ≈ Fe2O3 was favourable. The maximum of alizarin red S adsorption of PAC, treated PAC, and PAC/γ ≈ Fe2O3 was 24.5 mg/g, 57.8 mg/g, and 112.56 mg/g, respectively. The models of Langmuir and pseudo-first-order were a fit model to describe the adsorption isotherm and the Kinetic, respectively. The PAC/γ ≈ Fe2O3 is a promising class of the adsorbents in the adsorption of various dyes from textile effluents.

Data on the fluoride adsorption from aqueous solutions by metal-organic frameworks (ZIF-8 and Uio-66)

The variables examined were initial fluoride concentration, ZIF-8 and Uio-66 dosage, pH, and contact time. The residual concentration of fluoride was measured by a spectrophotometer. According to BET, the specific surface area of the ZIF-8 and Uio-66 was 1050 m2/g and 800 m2/g, respectively. Total pore volume and average pore diameter of the ZIF-8 and Uio-66 were 0.57 cm3/g, 0.45 cm3/g and 4.5 nm, 3.2 nm, respectively. The best pH for fluoride adsorption was neutral conditions. By increasing the ZIF-8 and Uio-66 dose, the fluoride uptake increased at first, but then decreased. Also, the maximum adsorption for ZIF-8 and Uio-66 was observed in adsorbent dose 0.2 and 0.6 g/L, respectively. The best model for describing kinetic and isotherms of fluoride adsorption were the pseudo-second-order model and Langmuir isotherm model, respectively. Based on the Langmuir model, the adsorption capacity of fluoride by ZIF-8 and Uio-66 was reported to be 25 mg/g and 20 mg/g, respectively.