Use of Cu(II) catalyst assisted oxidative decolorization of dye by chlorinating species in water: A kinetic and mechanistic study with acid red1 dye

A quick and easy decolorization method has been created in the current study to get rid of the Acid Red 1 (AR1) dye from the wastewater. At 298 K, the kinetics of oxidative decolorization of AR1 dye with Chloramine-B (CAB) in NaOH medium, catalyzed by copper(II) sulphate, have been examined spectrophotometrically (λmax = 506nm). The experimental rate laws found are as follows: d[CAB]/dt = k [CAB]0 [AR1]0 [Cu(II)]x / [OH−]y in an alkaline medium, where x and y are less than unity.Under ideal experimental conditions, 90% dye decolorization is achieved in 30 minutes using concentrations of 0.003M [CAB], 0.0003M [AR1], 0.003M [Cu(II), and 0.003M [OH−].In the current kinetic redox system, the Cu(II) catalyst showed to be an effective homogeneous catalyst. The 4-acetamido-5,6-dioxo-5,6-dihydro naphthalene-2-sulphonic acid is identified as the oxidation product using mass spectrum analysis. The FTIR spectra show the absence of N=N stretching bands at 1489 cm−1 which confirms the oxidative breakdown of the azo group, a fundamental chromophore responsible for color, which induces toxicity in the waste water. The decolorization reaction catalyzed by Cu(II) is approximately six times faster than the uncatalyzed reaction. The catalytic constant (Kc) is calculated at various temperatures, and activation parameters for copper(II) are also evaluated. The observed results are explained by plausible mechanisms, and relative rate laws has been deduced. Chemical oxygen demand (COD) has been significantly reduced by the oxidative decolorization process. Phytotoxicity tests revealed that the treated dye sample is less toxic than the untreated dye sample. An economic analysis is carried out. Notably, with appropriate modifications, the developed oxidative decolorization technique is expected to benefit in the removal of AR1 dye present from industrial wastewater

Recent advances in the development of high efficiency quantum dot sensitized solar cells (QDSSCs): A review

Quantum dots play an important role in third-generation photovoltaics. The key focus on quantum dots is due to their cost effect, capacity to work in diffused light, ease of fabrication, light weight, and flexibility which pique curiosity to further research. The incorporation of quantum dots into photovoltaics results in theoretically high thermodynamic conversion efficiencies of up to 40%, but in practise, the efficiencies are lower than those of dye-sensitized solar cells. Recent developments of different components like photoanode, quantum dot sensitizer, electrolyte, and counter electrode were discussed in detail. It was observed that by changing the synthesis methods, the adhesion properties might vary, which leads to enhancing the photovoltaic properties such as power conversion efficiency (PCE), open circuit voltage (Voc), short circuit current (Jsc), and fill factor (FF). The first report on the efficiency of Quantum Dot Sensitized Solar Cells (QDSSCs) was 0.12%. As of today, the efficiency is reported as 18.1 %, and further, the researchers are working to improve the efficiency of QDSSCs