Optimization of free chlorine, electric and current efficiency in an electrochemical reactor for water disinfection purposes by RSM.
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ABSTRACT:
SUBMITTER: Naderi M
PROVIDER: S-EPMC7721780 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The degradation efficiency of chloroquine phosphate (CQ), an anti-COVID-19 drug, was investigated in a flow-by electrochemical reactor (FBER) provided with two boron-doped diamond (BDD) electrodes (as cathode and anode) under batch recirculation mode. A central composite rotatable design (CCRD) was run down to model and assess the influence of initial pH in an interval of 3.71 to 11.28, the current density in an interval of 34.32 to 185.68 mA cm−2, and liquid volumetric flow rate in an interval of 0.58 to 1.42 L min−1, and conduct the convex optimization to obtain the maximum degradation efficiency. Experimental results were modeled through a second-order polynomial equation having a determination coefficient (R2) of 0.9705 with a variance coefficient of 1.1%. Optimal operating conditions found (initial pH of 5.38, current density (j) of 34.4 mA cm−2, and liquid flow rate (Q) of 1.42 L min−1) led to a global maximum degradation efficiency, COD removal efficiency, and mineralization efficiency of 89.3, 51.6 and 53.1%, respectively, with an energy consumption of 0.041 kWh L−1 within 9 h of treatment. Additionally, a pseudo-zero-order kinetic model was demonstrated to fit the experimental data and the calculated pseudo-zero-order kinetic constant (kapp) was 13.14 mg L−1 h−1 (2.54 × 10−5 mol dm−3 h−1). Furthermore, the total operating cost was of 0.47 US$ L−1. Finally, this research could be helpful for the treatment of wastewater containing an anti-COVID-19 drug such as CQ. Supplementary Information The online version contains supplementary material available at 10.1007/s10008-023-05452-7.
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Project description:The control of cellular processes by direct electronic interface will facilitate the development of biosensors, synthetic biology, and nanobiotechnology by providing the means to pass information from synthetic to living elements of hybrid systems. To investigate the potential of manipulating cellular gene expression by means of electric current, Escherichia coli cultures were screened for electric current inducible genes using global gene expression profiling. Cells in stationary phase were subjected to a DC current density of 2.5 mA/cm2 for 2 min after which the cells were lysed and the total RNA extracted. Of the 4290 expressed genes in E. coli , 432 genes were found to be significantly differentially expressed at an effective alpha value of 5.8 X 10-6. Of these, 333 genes were induced and 99 repressed. Several genes were verified as differentially expressed by quantitative real-time RT-PCR. The set of differentially expressed genes were examined for the presence of regulatory factors, subsidiary regulon genes, and biological function, particularly redox functions. Transcripts for the regulatory proteins fnr, sspB, soxS, oxyR, creB and yeiL were found to be up-regulated, and crp was down regulated. While soxS and oxyR were up-regulated, the downstream genes controlled by these regulatory proteins were not differentially expressed, suggesting that the oxidative stress level of low-current electric exposure is small. Genes controlled by FNR and CRP, many of which have redox function, were found to be differentially expressed suggesting modulation by direct reduction that can only be partially explained as a response to the reducing environment created by the electrolytic generation of H2 at the cathode. Genes associated with phosphate metabolism and membrane proteins were also differentially expressed. Three biological replicates were exposed to electric current along with three biological replicate controls.
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