Parametric study and process modeling for metronidazole removal by rhombic dodecahedron ZIF-67 crystals.

Metronidazole (MNZ) is an extensively used antibiotic against bacterial infections for humans and farm animals. Prevention of antibiotics discharge is essential to prevent adverse environmental and health impacts. A member of metal-organic frameworks, zeolite imidazole framework-67 with cobalt sulfate precursor (ZIF-67-SO4) and exceptional physio-chemical properties was prepared via room temperature precipitation to adsorb MNZ. The study framework was designed by Box-Behnken Design to evaluate the effect of pH, ZIF-67-SO4 dose, and contact time on adsorption efficiency. The polynomial model fitted the adsorption system indicated the optimal condition for 97% MNZ removal occurs at pH = 7, adsorbent dosage = 1 g/L, and mixing time = 60 min. The model also revealed that the removal increased with contact time and decreased at strong pH. Equilibrium and kinetic study also indicated the adsorption of MNZ followed the intra-particle diffusion model and the Langmuir isotherm model with a qmax = 63.03 mg/g. The insignificant loss in removal efficacy in use-reuse adsorption cycles reflected the practical viability of ZIF-67-SO4.

Application of health belief model to predict COVID-19-preventive behaviors among a sample of Iranian adult population.

BACKGROUND: The novel coronavirus (COVID-19) has infected nearly 9.5 million people in 216 countries, areas, or territories in the world. The fight against the COVID-19 has become a very serious international challenge. The aim of this study was to determine the predictors of COVID-19-preventive behaviors using the health belief model (HBM). MATERIALS AND METHODS: This cross-sectional study was conducted with the participation of 558 samples from the adult population of Iran. The online convenience sampling was conducted in this research. The online 68-item questionnaire link was published all over Iran through social networks including Telegram and WhatsApp, which are common in Iran. The data were analyzed using SPSS software version 19. Descriptive statistics, bivariate Pearson's correlation test, and multiple linear regression were used to analyze the data. RESULTS: The mean age of the subjects was 33.3 ± 10.01 years. The participants were often female (61.3%), married (57.9%), and resident of the city (81.0%) with university educational level (78.8%). The results showed that the HBM structures predicted 29.3% of the preventive behaviors of COVID-19 in the subjects. The perceived benefits, perceived barriers, and self-efficacy significantly predicted the preventive behaviors, but the perceived susceptibility and perceived severity were not significant in the regression model. The internet and virtual social networks (49.8%), broadcast (33.5%), and healthcare providers (15.8%) were the most important sources of information related with COVID-19. In response to COVID-19-related internal cues to action, 36.6% did not pay attention and 34.7% tried to self-medicate. Only 28.5% of the subjects referred to the hospital, healthcare center, or physician. CONCLUSION: Self-efficacy, perceived barriers, and perceived benefits were the key determinants of COVID-19-preventive behaviors in the subjects. It can be concluded that the HBM is a good tool to predict COVID-19-preventive behaviors in Iranian population.

Effective adsorptive removal of reactive dyes by magnetic chitosan nanoparticles: Kinetic, isothermal studies and response surface methodology.

In the present study, magnetic chitosan (MC) was synthesized, characterized, and used as an efficient adsorbent for the removal of Reactive Red 141 (RR-141) and Reactive Yellow 14 (RY-14) dyes. Synthesized magnetic chitosan nanoparticles were used for characterization with the help of scanning electron microscope (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), and X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). The effect of the pH, concentration of pollutants, and adsorbent dosage on the amount of adsorption was studied. Under optimum conditions, the removal rate of RR-141 and RY-14 was 99.5 and 92.7%, respectively. The maximum adsorption capacities were obtained 98.8 and 89.7 mg/g for the RR141 and RY-14, respectively. The results from isotherm models showed that the adsorption of dyes on magnetic chitosan nanocomposite correlated well with Freundlich model, whereas the kinetics studies revealed that the adsorption process was fitted by pseudo-first-order for both dyes. Results of the reusability tests confirmed the magnetic chitosan (MC) nanoparticles could be used for several times. Based on the experimental results obtained, the MC has adequate potential for the treatment of water contaminated with anionic dyes.

Removal of Penicillin G from aqueous solutions by a cationic surfactant modified montmorillonite.

Nowadays, antibiotics have been found in the effluents of many pharmaceutical industries and hospitals, sanitary sewage, surface water and groundwater. The purpose of this study was to investigate the possibility of using Hexadecyl Trimethyl Ammonium Bromide modified montmorillonite (HDTMA-Mt) as an inexpensive and suitable adsorbent for the removal of Penicillin G from aqueous solutions. The experiments were conducted in a batch system. The effects of different variables including surfactant loading onto the clay, solution pH, contact time, adsorbate concentration and temperature were investigated on the removal of Penicillin G. Surface properties of the clay were evaluated using X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) techniques. Various isotherms (Langmuir and Freundlich) and kinetics (pseudo-first order, pseudo-second order and intraparticle diffusion models) of adsorption were studied for the data evaluation. The findings indicated that the sorption capacity of the modified clay was found to be 88.5 mg/g over 60 min contact time at pH 9. The pseudo-second kinetic (R2 = 0.999) and Freundlich isotherm (R2 = 0.915) models best fitted the experimental data of Penicillin G by the adsorbent. The negative values of ΔG at higher temperature and positive value of ΔH showed the endothermic and spontaneously sorption of the drug by the clay. It can be concluded that the modified clay can be considered as a cheap and eco-friendly sorbent for the removal of Penicillin G from water and wastewater.

Evaluation of phosphate removal from aqueous solution using metal organic framework; isotherm, kinetic and thermodynamic study.

BACKGROUND: Phosphate (PO4 3-) is the main etiological factor of eutrophication in surface waters. Metal organic frameworks (MOFs) are novel hybrid materials with amazing structural properties that make them a prominent material for adsorption. METHODS: Zeolitic imidazolate framework 67 (ZIF-67), a water stable member of MOFs, with a truncated rhombic dodecahedron crystalline structure was synthesized in aqueous environment at room temperature and then characterized using XRD and SEM. PO4 3- adsorption from synthetic solutions using ZIF-67 in batch mode were evaluated and a polynomial model (R2: 0.99, R2 adj: 0.98, LOF: 0.1433) developed using response surface methodology (RSM). RESULTS: The highest PO4 3- removal (99.2%) after model optimization obtained when ZIF-67 dose, pH and mixing time adjusted to 6.82, 832.4 mg/L and 39.95 min, respectively. The optimum PO4 3- concentration in which highest PO4 3- removal and lowest adsorbent utilization occurs, observed at 30 mg/L. PO4 3- removal eclipsed significantly in the presence of carbonate. The equilibrium and kinetic models showed that PO4 3- adsorbed in monolayer (qmax: 92.43 mg/g) and the sorption process controlled in the sorption stage. Adsorption was also more favorable at higher PO4 3- concentration, according to the separation factor (KR) graph. Thermodynamic parameters (minus signs of ∆G°, ∆H° of 0.179 KJ/mol and ∆S° of 44.91 KJ/mol.K) demonstrate the spontaneous, endothermic and physisorption nature of the process. CONCLUSION: High adsorption capacity and adsorption rates, make ZIF-67 a promising adsorbent for PO4 3- removal from aqueous environment.

Analysis of quality and quantity of health-care wastes in clinical laboratories: a case study of Ilam city.

Generation of health-care wastes is one of the major concerns in health-care institutions worldwide due to direct and indirect impact on human health and environment. The purpose of the present work was to estimate the quantity and quality of clinical laboratory wastes in the city of Ilam, Iran. In this cross-sectional study, randomly eight clinical laboratories including five in private sector and three governmental clinical laboratories were selected for sampling according to the purpose of the study. The results showed that the total amount of waste generation was 27,700.90 kg/year. The average amount of health-care wastes generation in Ilam city was 0.2 kg/person/year. The portions of general, pathologic, sharp, infectious, and pharmaceutical and chemical wastes were 37, 5, 2, and 56% (by weight), respectively. As a considerable amount of waste is generated in clinical laboratories of Ilam city, therefore, it is necessary to implement integrated plans for the proper management of these wastes. Thus, sufficient training and education programs must be developed for all clinical staffs and that the existing training and education procedures should also be promoted.

Data on the removal of turbidity from aqueous solutions using polyaluminum chloride.

Polyaluminum chloride (PAC) is claimed to be superior to conventional coagulants because of higher removal of particulate and/or organic matters as well as inherent advantages of lower alkalinity consumption and lesser sludge production. 1000 mL of the reaction mixture was examined using parameters, including PAC dose (5-10 mg/L), pH (4-9), and turbidity (1.9 NTU). The content was stirred at 120 rpm for 1 min. Thereafter, the turbidity of water samples was measured using a P2100 turbidimeter. Data indicated that the maximum removal efficiency of turbidity (97.74%) obtained under the PAC doses of 4 and 10, and the pH of 8. There is not a significant relationship between the different dosages of PAC (P-value > 0.05), but the influence of pH on the removal of turbidity was significant (P-value < 0.05). Based on the dataset, the removal efficiency of turbidity was depended on PAC and pH.

Food Safety Knowledge and Practices of Male Adolescents in West of Iran.

BACKGROUND: Every year many people around the world become infected with food-borne infections. Insufficient knowledge and skills related to food safety and hygiene are among the factors affecting the incidence of food-borne diseases, especially in adolescents. AIM: The purpose of this study was to determine the knowledge and practices associated with food safety and hygiene in Ilam city male adolescents. MATERIAL AND METHODS: Three hundred and eighty of male adolescents aged 13 to 19 were selected randomly and entered the cross-sectional study. Data were collected using a researcher-made questionnaire From December 2016 to February 2017. Descriptive statistics, Pearson correlation, independent t-test and one-way ANOVA were used to analyse the data in SPSS software (version 19.0). RESULTS: The findings of the study showed a positive and significant relationship between knowledge and practices related to food safety and hygiene (r = 0.122; p = 0.018). Also, the findings showed that food safety knowledge and practice of adolescents were significantly affected by the level of their education, parental education level, parental employment status and household economic conditions, (p < 0.005). Also, the results showed that the participants generally obtained 57.74% of the knowledge score and 57.63% of practices score. The subjects had the most knowledge about food supply and storage (60%), and the highest practice was related to personal and environmental hygiene, (61.73%). CONCLUSION: The inadequacy of knowledge and performance of adolescents about food safety and hygiene shows the need for implementation of health education interventions in this area.

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/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. 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 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%. 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/H2O2 process.