Determination of optimal operating conditions for AC-powered electrocoagulation process coupling green additive Tartaric Acid to remove Ni2+: Pyomo and RSM approach.

A novel Python-based open-source optimization framework, namely Pyomo (Python optimization modeling objects), alongside a conventional optimization method, RSM (response surface methodology), was utilized to determine the optimal operating conditions of an alternating current-powered electrocoagulation (ACPE) process for nickel removal. In this regard, four mutable operating factors, current density (5-9 mA/cm2), initial nickel concentration (200-400 mg/L), initial pH of the solution (5-9), and electrolysis time (30-60 min), along with a fixed amount of an additional eco-friendly substance, Tartaric Acid (155 mg/L) were considered. Metal removal efficiency (OF1) and operating costs (OF2) were monitored and evaluated as objective functions with the aim of maximization and minimization, respectively. Experiments were conducted according to the central composite design (CCD), and validation outcomes established a reasonable agreement between the predicted models and the experimental data. The multi-objective optimization process yielded two sets of 30-optimal-solution obtained through Pyomo and RSM. Accordingly, the proposed solutions by the Pyomo were found to be more flexible and eclectic, supplying the local decision maker(s) with a diverse spectrum of optimal operating conditions. Adding TA was also effective in reducing electrical energy consumption by up to 46%.

Evaluation of energy and electrode consumption of Acid Red 18 removal using electrocoagulation process through RSM: alternating and direct current.

This study aims to evaluate energy and electrode consumption for Acid Red 18 (AR18) removal and the operating costs employing alternating current (AC) and direct current (DC) in an electrocoagulation (EC) system. As the novelty of this study, the effects of AC/DC mode and electrode type were scrutinized through a series of designed experiments in a batch EC reactor to remove a globally used Azo dye from wastewater. In this regard, by designing the experiments with response surface methodology (RSM), four series of 30 experiments were separately conducted employing DC and AC for iron (Fe) and aluminum (Al) electrodes. In each series, quadratic models were achieved for the removal efficiency and operating costs; by confirming the accuracy of the models, two responses were simultaneously optimized accordingly. As a result, the AR18 removal efficiency with Al electrodes had no significant difference using AC and DC (on average 0.2% difference); however, for Fe electrode, the EC performance in DC was more significant than AC (on average 13.8% difference). Also, the operating costs of Fe electrode were more economical in comparison with the Al; on average, the operating costs in the case of applying DC for Fe and Al were achieved 14.6 and 39.8 (US$/kg dye removed), respectively; whereas, for AC, this amount was calculated 9.3 and 36.0 (US$/kg dye removed) for Fe and Al, respectively.

Positive environmental effects of the coronavirus 2020 episode: a review.

The outbreak of COVID-19 has made a global catastrophic situation that caused 1,039,406 deaths out of 35,347,404 infections, and it will also cause significant socio-economic losses with poverty increasing from 17.1 to 25.9%. Although the spreading rate of COVID-19 is very high on October 6, 2020, the death rate is still less than 2.94%. Nonetheless, this review article shows that the lockdown has induced numerous positive impacts on the environment and on energy consumption. For instance, the lockdown has decreased the electricity demand by 30% in Italy, India, Germany, and the USA, and by 12-20% in France, Germany, Spain, India, and the UK. Additionally, the expenditure of the fuel supply has been decreased by 4% in 2020 as compared to the previous years (2012-2019). In particular, The global demand for coal fuel has been reduced by 8% in March and April 2020 as compared to the same time in 2019. In terms of harmful emissions, the lockdowns reduced the emissions of nitrous oxides by 20-30% in China, Italy, France, Spain, and by 77.3% in São Paulo, Brazil. Similarly, the particulate matter level has been reduced from 5-15% in Western Europe, to 200% in New Delhi, India, which in turn has enhanced the air quality in a never-seen manner in recent times. In some places, such as New York, USA, CO2 emission was also reduced by 5-10%. The water quality, in several polluted areas, has also been remarkably enhanced, for example, the dissolved oxygen content in the Ganga River, India, has increased by about 80%. Traffic congestion has also been reduced worldwide, and in some areas, it has been reduced by 50%, such as New York and Los Angeles, USA. Overall, while the COVID-19 pandemic has shrinked the global economy by 13-32%, the pandemic has also clearly benefited to other sectors, which must be considered as the spotlight for the permanent revival of the global ecosystem.

Simultaneous removal of nitrate and nitrite using electrocoagulation/floatation (ECF): A new multi-response optimization approach.

This study aims to remove both nitrate and nitrite from wastewater as well as modeling and simultaneous optimizing the electrocoagulation/floatation (ECF) process with 3 responses, namely, the residual nitrate, the residual nitrite and the operating costs; so that all responses meet the standard limitations. For this purpose, 57 experiments designed by the response surface method (RSM) were carried out. The effect of selected variables, including initial pH, current intensity, initial nitrate concentration, number of electrodes, reaction time and their interactions were evaluated. The analysis of variance (ANOVA) confirmed that the predicted equations were in reasonable agreement with the experimental data for three responses. To reach a new multi-response optimization approach, a code was developed in MATLAB software, which was applied to optimize the responses all together. Eight optimized conditions were obtained in accordance with the residual nitrate and the residual nitrite of less than 50 mg/L and 10 mg/L, respectively, and the limited operating costs to 10 ±â€¯0.05 US$/(kg NO3-removed).

Evaluation of direct and alternating current on nitrate removal using a continuous electrocoagulation process: Economical and environmental approaches through RSM.

This study aims to investigate the effects of alternating current (AC) and direct current (DC) for nitrate removal and its operating costs by using a continuous electrocoagulation (CEC) process. For this purpose, two series of 31 experiments, which were designed by response surface method (RSM), were carried out in both cases of the AC and the DC modes. In each series, the effect of selected parameters, namely, initial nitrate concentration, inlet flow rate, current density and initial pH along with their interactions on the nitrate removal efficiency as well as its operating costs, as responses, were investigated separately. According to the analysis of variance (ANOVA), there is a reasonable agreement between achieving results and the experimental data for both responses. The nitrate removal in the AC mode was slightly more efficient than that of the DC mode. In addition, the average operating costs of the DC mode, including the energy and the electrode consumption for the CEC process were achieved 54 US$/(kg nitrate removed); whereas this amount was calculated 29 US$/(kg nitrate removed) for the AC mode. Therefore, the average of the operating costs was improved more than 40% using the AC mode, which was mainly related to reduction of aluminum electrode consumption.