Efficacy of exopolysaccharide in dye-laden wastewater treatment: A comprehensive review.

The discharge of dye-laden wastewater into the water streams causes severe water and soil pollution, which poses a global threat to aquatic ecosystems and humans. A diverse array of microorganisms such as bacteria, fungi, and algae produce exopolysaccharides (EPS) of different compositions and exhibit great bioflocculation potency to sustainably eradicate dyes from water bodies. Nanomodified chemical composites of EPS enable their recyclability during dye-laden wastewater treatment. Nevertheless, the selection of potent EPS-producing strains and physiological parameters of microbial growth and the remediation process could influence the removal efficiency of EPS. This review will intrinsically discuss the fundamental importance of EPS from diverse microbial origins and their nanomodified chemical composites, the mechanisms in EPS-mediated bioremediation of dyes, and the parametric influences on EPS-mediated dye removal through sorption/bioflocculation. This review will pave the way for designing and adopting futuristic green and sustainable EPS-based bioremediation strategies for dye-laden wastewater in situ and ex situ.

A critical review on remediation of microplastics using microalgae from aqueous system.

Microplastics (MPs) are deemed to be a global concern due to their harmful negative effects on the aquatic environment and human beings. MPs have a significant impact on both fresh and marine water ecosystems. In many countries, there is concern about the deleterious consequences of MPs on human health due to the presence of MPs in aquatic life for higher intake of marine food (fish and shellfish). Exposure to MPs causes fish to suffer from growth retardation, neurotoxicity, and behavioural abnormalities and it affects human as well. It causes oxidative stress, neurotoxicity, cytotoxicity, and immune system disruption after being ingested to these contaminated fish in human body. Due to these reasons, it has become imperative to find ways to resolve this problem. This review paper represents a pioneering endeavor by consolidating comprehensive information on microplastic-polluted Indian riverine ecosystems and effective MPs removal methods into a single, cohesive document. It meticulously evaluates the principles, removal efficiency, benefits, and drawbacks of various techniques, aiming to identify the most optimal solution. Furthermore, this paper provides a comprehensive exploration of the interesting interactions between MPs and microalgae, delving into the intricate processes of hetero-aggregation. Additionally, it shines a spotlight on the latest advancements in understanding the efficacy of microalgae in removing MPs, showcasing recent breakthroughs in this field of research. Moreover, the work goes beyond conventional assessments by elucidating the characteristics of MPs and exploring diverse influencing parameters that impact MPs removal by microalgae and also addresses the potential future aspects. This thorough investigation uncovers important factors that could significantly contribute to the development of more efficient and sustainable remediation strategies.

Modeling and optimization of process variables for HCl gas removal by response surface methodology.

In the present article, optimization of process variables has been done to maximize the removal efficiency of toxic HCl gas in a submerged self-priming venturi scrubber. Response surface methodology with central composite design has been chosen to predict the effect of process variables on the removal efficiency. A quadratic equation was found from this study to predict the removal efficiency and from the ANOVA test, the significance of process variables was evaluated. Regression analysis confirmed the suitability of the developed model by the higher R2 square value (0.9717). Optimum conditions were obtained as 55.18 m s-1 of throat gas velocity, 405.10 ppm of inlet HCl concentration and 0.0038 N of NaOH concentration in scrubbing liquid to achieve 90.80% of the HCl removal efficiency.

Removal of HCl gas from off gases using self-priming venturi scrubber.

Growing concern about the effect of hydrochloric acid gas (HCl) on environment and abatement of it is now a very serious issue. This present paper is focused on developing a realistic model in order to remove the HCl from the off gases using self-priming venturi scrubber. A detailed parametric study of throat gas velocity (36-72 m/s), liquid level in outer cylinder (0.40-0.77 m) and inlet concentration of HCl (100-500 ppm) on HCl removal efficiency have been done with normal water as a scrubbing liquid. Also the removal efficiency was enhanced by using NaOH solution as a scrubbing liquid in submerged and non-submerged conditions. Therefore, the maximum removal efficiency of HCl was obtained as 87.83% with normal water and 92.54% with 0.005N NaOH solution as the scrubbing liquid at inlet HCl concentration of 500 ppm, throat gas velocity of 60 m/s and liquid level of 0.77 m in submerged condition. Experimental results were validated with the developed empirical model and showed excellent agreement with less deviation.