Origin, types, and contribution of emerging pollutants to environmental degradation and their remediation by physical and chemical techniques.

The growing presence of emerging pollutants (EPs) in aquatic environments, as well as their harmful impacts on the biosphere and humans, has become a global concern. Recent developments and advancements in pharmaceuticals, agricultural practices, industrial activities, and human personal care substances have paved the way for drastic changes in EP concentrations and impacts on the ecosystem. As a result, it is critical to mitigate EP's harmful effects before they jeopardize the ecological equilibrium of the overall ecosystem and the sustainable existence of life on Earth. This review comprehensively documented the types, origins, and remediation strategies of EPs, and underscored the significance of this study in the current context. We briefly stated the major classification of EPs based on their organic and inorganic nature. Furthermore, this review systematically evaluates the occurrence of EPs due to the fast-changing ecological scenarios and their impact on human health. Recent studies have critically discussed the emerging physical and chemical processes for EP removal, highlighting the limitations of conventional remediation technologies. We reviewed and presented the challenges associated with EP remediation and degradation using several methods, including physical and chemical methods, with the application of recent technologies. The EP types and various methods discussed in this review help the researchers understand the nature of present-day EPs and utilize an efficient method of choice for EP removal and management in the future for sustainable life and development activities on the planet.

Impact of corrugated duct and heat storage element on the performance of a low-cost solar air heater under forced air circulation: an experimental study.

The need to address global warming issues and international policies has placed a greater emphasis on the development of solar energy utilization systems. Intensive study is necessary to expand solar energy applications, as solar energy potential varies widely. This study investigates the thermal and thermohydraulic performance of a modified flat plate solar air heater (FSAH) to assess the effects of using corrugated aluminium duct and sand heat storage elements (HSE) in various combinations. The different arrangements selected for the experimental investigation are the FSAH, FSAH with corrugated aluminium duct (FSAH-C), FSAH with a sand heat storage element (FSAH-S), and FSAH with a combined use of corrugated aluminium duct and a sand heat storage element (FSAH-CS). The materials used for fabrication are low-cost and readily available in the study area. The results indicate that the sand bed enhanced the thermal performance by acting as the thermal heat storage medium, which could also supply heat for a short duration after non-sunny hours, and the corrugated aluminium duct enhanced the surface area and allowed the air to pass twice inside the SAH. We observed that the SAHs with sensible heat storage had a higher top loss compared to the FSAH-S configuration. The average thermal efficiency of the FSAH-CS configuration was 59.17%, which is 8.81%, 5.72%, and 10.95% higher than FSAH-S, FSAH-C, and FSAH, respectively. Furthermore, this configuration achieved an exit temperature of 64.5 °C. The proposed system has a thermohydraulic efficiency of 59.14%, which is not significantly different from the average thermal efficiency. Therefore, the suggested system verifies its ability to function without requiring substantial external power.

Performance and environmental sustainability studies on a dual-fuel IC engine working with producer gas of variable calorific values from rural biomass.

Decentralized power generation using renewable gaseous biofuels faces challenges due to their inconsistent quality and availability. Mixing producer gas (PG) with diesel as a secondary fuel is a promising option, but the non-stable calorific value (CV) of PG from different biomasses poses a serious problem for the efficient operation of a dual-fuel engine. This study aims to examine how the CV of PG from various biomasses affects a 3.75-kW dual-fuel IC engine's performance. The experimental facility, which has a dual-fuel engine and a 115-kW thermal gasifier, tested the blends of diesel and PG from different biomasses. We chose biomass based on its availability and PG's CV of 3.4, 4.4, 5.2, and 6.3 MJ/Nm3. For this range of CV, the efficiency, energy consumption, and fuel replacement of a dual-fuel engine vary between 20.9 and 26.6%, 17.3 and 13.5 MJ/kWh, and 10.8 and 76.9%, respectively. Furthermore, the blend with the maximum CV of PG had a 69.64% lower specific diesel consumption and an 86% higher diesel replacement rate than the blend with the lowest CV of PG. In terms of emission characteristics, the comparison showed a 2.02-7.06% reduction in NOx and a 4.05-55.6% increase in hydrocarbons (HCs) for the tested conditions. The overall observations demonstrated that a significant enhancement in a dual-fuel engine's performance is possible with a higher CV of PG. However, the emissions trade-offs demand additional optimization studies, as well as case-based research, in order to integrate renewable energy and emission management in smaller-scale applications across more geographies.