Use of hybrid materials in the trace determination of As(V) from aqueous solutions: An electrochemical study

Abstract

The carbon paste electrode (CPE) was modified with the pristine bentonite and hybrid material (HDTMA-modified bentonite). The modified-CPEs are then employed as working electrode in an electrochemical detection of As(V) from aqueous solutions using the cyclic voltammetric measurements. Cyclic voltammograms revealed that As(V) showed reversible behavior onto the working electrode. The hybrid material-modified carbon paste electrode showed significantly enhanced electrochemical signal which was then utilized in the low level detection of As(V). Moreover, the studies were conducted at neutral pH conditions. The electrochemical studies were conducted with scan rates (20 to 200 mV/s) to deduce the mechanism of redox processes involved at the electrode surface. The anodic current was linearly increased, increasing the concentration of As(V) from 5.0 to 35.0 μg/g using the hybrid material-modified electrode. This provided fairly a good calibration line for As(V) detection. The presence of varied concentrations of As(III) in the determination of total arsenic was studied. The influence of several cations and anions viz., Cu(II), Mn(II), Zn(II), Pb(II), Cd(II), Fe(III), Cl-, NO3-, PO4 3-, EDTA and glycine in the detection of As(V) from aqueous solution was also studied. Further, in an attempt to simulate the real matrix analysis, the tap water sample was spiked with As(V) and subjected for As(V) detection using the modified-CPE.

Cathodic reduction characteristics of 2-chloro-4-nitrophenol in microbial electrolysis cell

“…On the one hand, the activity of electro-microorganisms was improved. On the other hand, electrons could directly attack 2C4NP adsorbed on the surface of microorganisms through the rapid transfer of microbial coenzymes, causing dechlorination, denitrated, or ring cleavage of 2C4NP [2,3,28]. In the samples of 36 h, the degradation efficiency of 2C4NP attained to more than 92% under the conditions of various applied voltages, while the degradation efficiency of 2C4NP was 85.9% when no voltage was applied.…”

“…Thereby, it's accelerated that the directional reduction conversion of the pollutants is presented in the cathode chamber. Furthermore, on the condition of an anaerobic environment, contaminants such as nitrobenzene [23], chlorophenol [24], antibiotics [25], and polychlorinated biphenyls [26] will be reduced at a low voltage in the cathode chamber of the MEC system, and at the same time, it also can produce electricity, which can effectively reduce the consumption of external power supply [27,28].…”

Metal organic framework (MOF): Synthesis and fabrication for the application of electrochemical sensing

“…The electrodes fabricated with suitable materials enabled a selective oxidation or reduction of the analyte to be obtained [24,25]. The suitable and strategic electrode alterations enhance the sensing capabilities of the working electrodes [26,27]. Many typical electrodes show poor surface kinetics and significantly decrease selectivity and sensitivity.…”

Influences of cathode potential and carbon source on parabromoaniline degradation in microbial electrolysis cell

“…This bioelectrochemical technique has attracted considerable attention from an increasing number of researchers because of its unique advantages of strong sustainability, high treatment efficiency, and low cost (Nanayakkara et al, 2019). Under anaerobic condition, pollutants such as nitrobenzene (Wang et al, 2012), chlorophenol (Wen et al, 2013), antibiotics (Kong et al, 2015), and polychlorinated biphenyl (PCB) (Yu et al, 2017) can be reduced effectively using MEC cathode when low DC voltage is applied; meanwhile, MET can also generate electric energy to reduce the external energy consumption (Korshin & Yan, 2018; Tiwari et al, 2017). Studies have shown that the dechloridation efficiency of biological anode for PCB is higher than ordinary anaerobic reactor under electrode potential of 0.2 V (Yu et al, 2016).…”