Optimization of electrocoagulation process for efficient removal of ciprofloxacin antibiotic using iron electrode; kinetic and isotherm studies of adsorption
Abstract: The present study focused on the removal of ciprofloxacin from hospital wastewater using electrocoagulation (EC) process by iron electrode and the kinetic and isotherms of adsorption were investigated. Response surface methodology (RSM) was used to evaluate the main effects of parameters, their simultaneous interactions and quadratic effect to achieve the optimum condition for EC process. The maximum removal rate was achieved at the current density of 15 mA·cm− 2, initial CIP concentration of 60 mg·L− 1, pH 7.5, inter-electrode distance 1.58 cm and electrolyte dose of 0.07 M NaCl within the equilibrium time of 20 min. The obtained experimental results are in good accordance with the Langmuir isotherm model for CIP adsorption on iron hydroxide by predicting the maximum adsorption capacity of 476.19 mg·g− 1. The predicted model for treatment of synthetic wastewater is in satisfactory agreement with real hospital wastewater treatment. First and second order kinetic models were studied to figure out the exact mechanism of the CIP removal using EC process. The obtained results revealed that the second order kinetic model best fitted the experimental results and suggested that the chemisorption mechanism controlled the adsorption of CIP. Under the optimal conditions of EC process, electrode consumption (ELC) and electrical energy consumption (EEC) were found to be 0.0625 g during a single run and 0.522 kWh·m− 3, respectively.
Summary (2 min read)
- The diabetes pandemic will increase from 175 million patients with diabetes in 2000 to 353 million in 2030.
- According to the national coronary artery disease (CAD) risk factors surveillance report, the overall prevalence of diabetes in Iran is estimated to be 8.7% in adults aged 15-64 years, of whom half (4.1%) were the newly diagnosed cases.
- It is not clear how many are at pre-diabetes stage and are prone to suffer from diabetes, or vice versa, with timely interventions, the disease can be prevented.
- 5 Using fasting plasma glucose (FPG) ≥7.2 mmol/L the criteria for poor management of diabetes, about 57% of individuals with diagnosed diabetes had high level of plasma glucose.
- The authors reported the age-sex standardized prevalence of diabetes at all stages including pre-diabetes (pre DM) and diabetes (DM).
- The Kerman Coronary Artery Disease Risk Factors.
- Study is a population based cohort study with repeated surveys.
- The methodology of KERCADR study has been explained in detail elsewhere.
- Only those who were able and provided written informed consent were recruited into the study.
- The study protocol was approved by the Ethical committee of Kerman University of Medical Sciences, Iran (Permission No. 88/110KA).
Interview and measurements
- All details of the measurement are presented elsewhere.
- Part of the questionnaire that the authors used in this study included demographic information, cigarette smoking (yes/no), opium addiction (no/occasional/ dependent), the level of physical activity (low/moderate/ high), and the level of depression and anxiety (related BECK questionnaires).
- Subjects who had no previous history of diabetes or anti-diabetic medication, but turned out to have FPG ≥7 mmol/L at the recruitment were considered as undiagnosed diabetic cases.
- In the old definition, uncontrolled diabetes was specified as HbA1c >53 mmol/mol (>7%) for all individuals.
- The authors found that diabetes and susceptibility in to diabetes was very common in Kerman.
- All participants were asked not to eat for 12-14 h before coming to the clinic.
- Subjects who had FPG more than 5.6 mmol/L were recalled for another FPG test and HbA1c test (NYCOCARD Kit, Code 1042184, Austria).
- To measure serum lipid profiles, total cholesterol (KIMIA Kit, Code 890303, Iran) and triglycerides (KIMIA Kit, Code 890201, Iran) were also measured for all individuals.
- All statistical analyses were conducted under survey data analysis using STATAv.12 (StataCorp, 2011 College Station, TX, USA).
- For age-sex direct standardizations, the authors used Kerman population reported in census 2006.
- All prevalence rates were weighted according to the sampling weight (reciprocal of the probability of selection) and individual response rate.
- The data were presented as absolute and relative frequencies as well as 95% confidence intervals (95% CI).
- Univariate and multivariate logistic regression models were applied to determine the predictors of diabetes (both diagnosed and undiagnosed DM).
Undiagnosed and diagnosed diabetes
- There was nearly an equal prevalence of undiagnosed-DM in subpopulations regarding depression and physical activity.
- The prevalence of DM was diagnosed in 7.0% of occasional opium users, while it was 4.0% among dependent users.
- Seven percent of overweight and 7.6% of obese people had diagnosed-DM.
Diabetes mismanagement: old definition
- The uncontrolled-DM increased from 60% in young adults to 77.8% in elderly people.
- The frequency of uncontrolled-DM among people without and with (both insulin and non-insulin) treatment was 57.9% and 92.9%, respectively.
- The frequency of uncontrolled-DM varied from 76.1% among non opium users to 81.3% in dependent opium users.
- People with low physical activity had a higher frequency of uncontrolled-DM (79.4%), which decreased to 66.7% in people with high level of physical activity.
Predictors of diabetes
- In crude analysis, sex (male vs female), age, education, opium addiction, depression, increased BMI category, lower physical activity, and DM familial history turned to be potential significant predictors for DM (Table 3 ).
- While in the multivariate model, after removing confounding effects, it was shown that the odds diabetes increased significantly only by age group (AOR 5.0 to 18.2), depression (AOR 1.2), overweight and obesity (AOR 1.6, and 1.5), moderate and low physical activity, (AOR 1.5, and 1.4) and the positive familial history of DM (AOR 2.2).
- The other variables did not have a statistically significant association with diabetes.
- In their analysis, the authors found one out of four individuals living in an urban area in Iran either had impaired glucose level (pre-diabetes) or diabetes.
- In several studies, it has been reported that the prevalence of diabetes (diagnosed and undiagnosed), impaired glucose tolerance (IGT) and impaired fasting glucose (IFG) increased by age    is not similar between men and women.
- Regarding the effect of cigarette smoking and opium consumption, the results of this study showed almost no statistically significant effects on control of diabetes or odds ratio of predictors of diabetes (Tables 2,3 ).
- In rural areas, Iran has a well-developed primary health-care system, having Behvarz workers responsible for population-based prevention and control services.
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Cites background from "Optimization of electrocoagulation ..."
...One of the major human antibiotics of the fluoroquinolone family which is prescribed extensively is ciprofloxacin (Paul et al., 2010; Bajpai et al., 2014; Fries et al., 2016; Yoosefian et al., 2017; Hassani et al., 2017b)....
Cites background or methods from "Optimization of electrocoagulation ..."
...To evaluate the percentage effect of each operating factor on removal efficiency of AC, Pareto analyses were conducted according to the following relation (Yoosefian et al. 2017): (3) Y = 0 + n...
...Since the presence of CO3 anions may result in the precipitation of Ca2+ cations that form an insulating layer on the surface of the cathode and lead to increase in the ohmic resistance of the EF reactor (Khandegar and Saroha 2013; Yoosefian et al. 2017)....
...05) implies the validity of the quadratic model (Doltabadi et al. 2016; Yoosefian et al. 2017)....
...To conduct a successful study, RSM is applied to find a suitable approximation for the relation between independent main variables and response as expressed below (Ahmadzadeh et al. 2017; Yoosefian et al. 2017):...
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