Hexavalent chromium reduction and energy recovery by using dual-chambered microbial fuel cell.

Microbial fuel cell (MFC) technology is utilized to treat hexavalent chromium (Cr(VI)) from wastewater and to generate electricity simultaneously. The Cr(VI) is bioelectrochemically reduced to non-toxic Cr(III) form in the presence of an organic electron donor in a dual-chambered MFC. The Cr(VI) as catholyte and artificial wastewater inoculated with anaerobic sludge as anolyte, Cr(VI) at 100 mg/L was completely removed within 48 h (initial pH value 2.0). The total amount of Cr recovered was 99.87% by the precipitation of Cr(III) on the surface of the cathode. In addition to that 78.4% of total organic carbon reduction was achieved at the anode chamber within 13 days of operation. Furthermore, the maximum power density of 767.01 mW/m² (2.08 mA/m²) was achieved by MFCs at ambient conditions. The present work has successfully demonstrated the feasibility of using MFCs for simultaneous energy production from wastewater and reduction of toxic Cr(VI) to non-toxic Cr(III).

Improved defluoridation and energy production using dimethyl sulfoxide modified carbon cloth as bioanode in microbial desalination cell.

In the present study, carbon cloth (CC) was functionalized using dimethyl sulfoxide (DMSO) and employed as an excellent bioanode for improving defluoridation efficiency, wastewater treatment, and power output from a microbial desalination cell (MDC). The Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) analysis of DMSO modified carbon cloth (CCDMSO) confirmed the functionalization of CCDMSO, and the water drop contact angle of 0° ensured its superior hydrophilicity. The presence of -COOH (carboxyl), S[bond, double bond]O (sulfoxide) and O-C[bond, double bond]O (carbonyl) functional groups on CCDMSO aids in enhancing the performance of the MDC. Besides, cyclic voltametric and electrochemical impedance analysis revealed that CCDMSO had an excellent electrochemical performance with low charge transfer resistance. Replacing CC with CCDMSO as anode in MDC, the time required for 3,10 and 20 mg/L of initial fluoride (F-) concentrations in the middle chamber was reduced from 24 ± 0.75 to 17 ± 0.37, 72 ± 1 to 48 ± 0.70, and 120 ± 0.5 to 96 ± 0.53 h, respectively to meet the prescribed standards (1.5 mg/L). Furthermore, using CCDMSO, the anode chamber of MDC exhibited a maximum of 83% substrate degradation, and simultaneously, the power output is increased by 2-2.8 times. CCDMSO improved the power production from 0.009 ± 0.003, 1.394 ± 0.06 and 1.423 ± 0.15 mW/m2 to 0.020 ± 0.07, 2.748 ± 0.22 and 3.245 ± 0.16 mW/m2, respectively, for initial F- concentrations of 3,10, and 20 mg/L. Modifying CC with DMSO thus proved to be an efficient and simple methodology for enhancing the overall performance of MDC.

Trends, Extreme Events and Long-term Health Impacts of Particulate Matter in a Southern Indian Industrial Area.

The present study uses various statistical tools to understand the behaviour of PM2.5 and PM10 in the Kanjikode industrial area of Southern India. Annual PM2.5 and PM10 average concentrations in 2018-2020 were three times more than the World Health Organization-specified standards (5 and 15 µg m-3). The statistical distribution analysis suggested well-fitted lognormal and gamma distributions of 24-h average PM2.5 concentrations and gamma distributions of 24-h average PM10 concentrations. Trend analysis observed a notable monotonic increasing trend for 24-h average PM2.5 concentrations with an increasing magnitude of 0.43 µg m-3 per annum. A downward trend was found for 24-h average PM10 concentrations, with a decreasing magnitude of 0.2 µg m-3 per year. Extreme event analysis of PM2.5 and PM10 has provided the highest concentration levels expected in the coming 10 years, 193 and 165 µg m-3, respectively, higher than the Indian National Ambient Air Quality Standards and considered a public health threat. The health risk assessment by AirQ + emphasized that more than 15, 34, and 27 premature deaths caused by total mortality in 2018, 2019, and 2020 could have been prevented if PM2.5 concentrations in the Kanjikode industrial area did not exceed 10 µg m-3. Statistical analysis and health risk assessment suggested adopting various constructive and multipronged approaches to reduce pollution levels and develop a health risk management plan in the industrial region. Supplementary Information: The online version contains supplementary material available at 10.1007/s11270-023-06302-y.

A flexible and sensitive electrochemical sensing platform based on dimethyl sulfoxide modified carbon cloth: towards the detection of dopamine and carvedilol.

The determination of neurotransmitters and adrenoreceptor drugs is highly essential due to their specific functions in the human body. In this work, the determination of carvedilol (CAR) and dopamine (DA) was carried out using carbon cloth (CC), which was modified using a facile strategy of drop-casting dimethyl sulfoxide (DMSO). This induced the formation of functional groups without any loss in the structural integrity of CC. The DMSO modified CC (CC-DMSO) was used for the detection of CAR in the range of 1 nM to 10 µM with a limit of detection (LOD) of 120 pM. Similarly, the CC-DMSO was able to detect DA in the range of 10 pM to 10 µM with a highly promising LOD of 0.3 pM. A bending test was also carried out on the electrode and it could be seen that only a negligible variation in sensing capability was observed when the electrode was in the bent form. In addition, the detection of CAR and DA was also carried out in real samples such as human serum. This study reveals that this modification strategy can serve as a versatile and flexible sensing platform for the detection of CAR and DA together in real world medical scenarios.

Concentrating nutrients and recovering water and energy from source separated urine using osmotic microbial fuel cell.

This work presents the use of osmotic microbial fuel cell (OsMFC), for the first time, to concentrate nutrients and recover water and energy from source separated urine. Four sets of concentration of fresh urine as feed and NaCl as draw were examined: 10% fresh urine vs 0.25 M NaCl; 10% fresh urine vs 2 M NaCl; fresh urine vs 0.25 M NaCl; and fresh urine vs 2 M NaCl. A maximum water flux of 14.27 LMH was attained when 10% of fresh urine and 2 M of NaCl were used as feed and draw solutions, respectively. Additionally, OsMFC concentrates ~99% of TOC, TN, NH4+, and 100% of PO43- and NO3- from urine at the feed side. Polarization studies indicate that the power generation in OsMFC is related to the rate of change of conductivity and the initial conductivity of the anolyte. The maximum (0.12187 W m-3) and minimum power densities (5.3372 × 10-4 W m-3) were obtained for the conditions of fresh urine vs 0.25 M NaCl and 10% fresh urine vs 0.25 M NaCl, respectively. The study shows that OsMFC is an effective pretreatment process to concentrate nutrients from urine by recovering water and energy, simultaneously.

Liquid crystal polaroid glass electrode from e-waste for synchronized removal/recovery of Cr(+6) from wastewater by microbial fuel cell.

This study demonstrates the use of Liquid Crystal coated Polaroid Glass Electrode (LCPGE) material collected from disposed liquid-crystal display (LCD) computer monitor as electrodes in microbial fuel cell (MFC) for the simultaneous reduction/recovery of Cr(+6) from chromium wastewater. Fourier transform infrared spectrum (FT-IR) confirms the presence of NH2, CN, CO and OC and/or COC functional groups in LCPGE. An excellent electrochemical performance with distinct redox peaks were observed in cyclic voltammetry test (100 mV/s). The maximum current density of 110 mA/m(2) (10 mW/m(2)) was achieved by operating MFC in batch mode. At the cathode LCPGE (10.5 cm(2)) interface, toxic Cr(+6) ions readily accepted electrons and formed nontoxic Cr2O3 as confirmed by FT-IR and X-ray photoelectron spectroscopy analysis. Moreover, electrochemical impedance analysis shows that bacteria were readily attached to the surface of LCPGE (10.5 cm(2)) within 24 h in a Bioelectrochemical System (BES).