Volume 25 - 2023

Hazardous metal chromium is used extensively in many different industrial processes and is commonly found in industrial effluents. Hazardous pollutants such inorganic anions, metal ions, synthetic xenobiotics, and others have contaminated ground and surface waters in India and other parts of the world as a result of continued industrial expansion and agricultural development. This study uses betel seed powder and a fixed bed reactor (FBR) technology running at room temperature to extract chromium (VI+) from a synthetic water environment. The fixed-bed research included significant experiments such as the development of breakthrough curves (including the effects of starting Cr (VI+) concentration, BSF size, and flow rate) and bed-depth service time (BDST) approach. Betel Seed Powder was used as a biosorbent to remove Cr (VI+) from aqueous solution. The effects of several variables, including bed height (2.5, 5.5, and 7.5 cm), flow rate of 40, 60, and 100 ml/min, were investigated at an influent pH of 6.5. It was shown that as bed depth, flow velocity, and starting concentration rose, so did the exhaustion time. The biosorptive capacity of betel seed powder in fixed bed reactor tests was approximately 8–9 times higher than that of betel seed powder in continuous stirred batch reactor study. For the removal of Cr (VI+) by BSF, the BDST method achieved a higher bed efficiency of 98.9% and was ideal. The biosorptive ability of BSP was found to be highly correlated with the initial Cr (VI+) concentration (No = 0.089Co).

Dyes play a crucial role in various industries, but their environmental impact and potential health risks have raised concerns. This review paper examines the classification and applications of dyes, highlighting the challenges posed by synthetic dyes and the growing interest in natural dyes. The impact of textile dyes on human health, ecosystems, water, soil, and air emissions is explored. The focus then shifts to sustainable dyeing practices in the denim industry, which can significantly reduce its environmental footprint and enhance product sustainability. The adoption of sustainable dyes aligns with circular economy principles, leading to energy and water savings. Collaboration, consumer awareness, and the integration of Life Cycle Assessment (LCA) are essential for driving sustainable dye adoption and promoting circular economy principles. The role of Environmental, Social, and Governance (ESG) factors in sustainable denim dyeing is emphasized, encompassing environmental, social, and governance considerations throughout the supply chain. The need to address greenwashing and validate sustainability claims is discussed, highlighting the importance of certifications and transparency. Chemical dyes are recognized as key contributors to achieving sustainability targets in the denim industry, aligning with the Science Based Targets initiative (SBTi) and reducing carbon emissions. The review concludes by stressing the importance of sustainable dyeing practices, considering water and energy usage, waste generation, and emissions, to minimize the denim industry's environmental impact and achieve sustainability objectives.

Dual-chamber microbial fuel cell (MFC) was constructed to treat heavy metal wastewater (Pb2+ solution). The results showed the maximum voltage, the maximum electric power density and pb2+ removal were 9.6 mV, 371.0 mV/m2 and 52.3% respectively. The effects of different cathode chamber environments on the production potential (V, volts) and Pb2+ removal rate of strained CD-1 were investigated. The results show that when the cathode chamber is soil, the maximum voltage is 8.88mV, and when the cathode chamber is solution, the maximum voltage is 12.11mV. The removal efficiency of heavy metals polluted from near to far from the electrode plate in the soil is 68.9%, 62.1%, 57.5%, and the removal efficiency of heavy metals in the solution is 67.46%. It can be concluded that when the soil is the cathode chamber. The removal rate of local heavy metals was the highest. When the solution was used as a cathode chamber, the average removal rate of heavy metals was the highest. The bacteria, named strain CD-1, as the electricity production bacteria (EPB) used in the dual chamber microbial fuel cell (MFC), was isolated from activate sludge and identified on its morphology, physichemical properties and phylogenetic positions. The results indicated that strain CD-1 was Gram-negative, rod. Oxidase and catalase reactions were positive. Strain CD-1 could use gluconate, lactose, D-fructose, L-Arabinose, D-arabinose, acetate, propionate, butyrate, lactate, sucrose and glucose, not use melibiose, galactose, N-acetylglucosamine, ethanol and glycerol.16S rRNA gene sequences analysis showed that strain CD-1 was most related to Ochrobactrum sp. (AJ245941）with the homology similarities of 98%. Based on the above results, strain CD-1 was belonged to the genus of Ochrobactrum and seemed to represent a novel species.

Because of its better physio-chemical qualities, biofuel is indeed a viable substitute source of energy for diesel vehicles. The biofuels used in this study is synthesized from pumpkin seed oil using the esterification reaction technique. The biodiesel was synthesized under ideal conditions and was employed to evaluate the impact of injection pressure varying from 200 to 275 bar in 25 bar increments and was tested for its effectiveness, combustions and the emission performance of 1 cylinder, 4 stroke DI diesel engine at a regular momentum of 1500 rpm using 25% Pumpkin seed biodiesel (PSBD25). The outcomes demonstrated that the BTE of PSBD25 be raised by 1.68 %, the release of CO, HC, and smoke were diminished, but NO emissions were boosted at higher IP of 250 bar compared to the standard IP of 200bar. Pressure of Cylinder and heat release rate for PSBD25 were increased for PSBD25, but ignition delay was shortened when compared to PSBD25 at standard IP of 200 bar. It is concluded that, there is a greater progress in performance and ignition features, as well as a reduction in exhaust gas release for PSBD25 with the exception of NO emissions at 250 bar IP at maximum load conditions.