Citation: Singh, A.; Tyagi, P.; Ranjan, R.; Sushkova, S.N.; Minkina, T.; Burachevskaya, M.; Rajput, V.D. Bioremediation of Hazardous Wastes Using Green Synthesis of Nanoparticles. Processes 2023, 11, 141. https://doi.org/10.3390/pr11010141 Academic Editor: Raluca Maria Hlihor Received: 9 November 2022 Revised: 26 December 2022 Accepted: 28 December 2022 Published: 3 January 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). processes Review Bioremediation of Hazardous Wastes Using Green Synthesis of Nanoparticles Ayushi Singh 1 , Parul Tyagi 1 , Rajiv Ranjan 1, *, Svetlana N. Sushkova 2 , Tatiana Minkina 2 , Marina Burachevskaya 3 and Vishnu D. Rajput 2, * 1 Department of Botany, Dayalbagh Educational Institute, Dayalbagh, Agra 282005, India 2 Academy of Biology and Biotechnology, Southern Federal University, 344006 Rostov-on-Don, Russia 3 Soil Chemistry and Ecology Laboratory, Faculty of Natural Sciences, Tula State Lev Tolstoy Pedagogical University, Lenin Avenue, 125, 300026 Tula, Russia * Correspondence: rajivranjan@dei.ac.in (R.R.); rajput.vishnu@gmail.com (V.D.R.) Abstract: Advanced agronomic methods, urbanisation, and industrial expansion contaminate air, wa- ter and soil, globally. Agricultural and industrial activities threaten living biota, causing biodiversity loss and serious diseases. Strategies such as bioremediation and physiochemical remediation have not been effectively beneficial at treating pollutants. Metal-based nanoparticles (NPs) such as copper, zinc, silver, gold, etc., in various nanoformulations and nanocomposites are used more and more as they effectively resist the uptake of toxic compounds via plants by facilitating their immobilisation. According to studies, bio-based NP synthesis is a recent and agroecologically friendly approach for remediating environmental waste, which is effective against carcinogens, heavy metal contamination, treating marine water polluted with excessive concentrations of phosphorus, nitrogen and harmful algae, and hazardous dye- and pesticide-contaminated water. Biogenic resources such as bacteria, fungi, algae and plants are extensively used for the biosynthesis of NPs, particularly metallic NPs. Strategies involving green synthesis of NPs are nontoxic and could be employed for commercial scale production. Here, the focus is on the green synthesis of NPs for reduction of hazardous wastes to help with the clean-up process. Keywords: green technology; metal-based nanoparticles; pollutant; toxic dyes; heavy metals 1. Introduction The combination of two sciences, i.e., nanotechnology and biotechnology, is gradually expanding its roots in almost all the sectors involving biology, engineering, cosmetics, remediation, biomedical, agriculture, food, etc. Numerous nanoscale (below 100 nm) materials show remarkable features in contrast to their bulk elements and components. With progressive studies, researchers have developed nano-based composites and materials, and found their effective application in almost every field including waste remediation, solar applications, and nano-sensors [1–3]. Economic development and accelerated industrial growth have overall resulted in higher environmental pollution through more energy expenditure, release of hazardous wastes, emission of toxic gases [4], and exhaust emissions from the automobile industry [5]. Hazardous wastes include various dyes (Azure-B, Disperse orange I, Disperse Red I, Crystal Violet, Basic Red 9, Sudan I) eluted from textile industries [6], toxic heavy metals [7,8], pes- ticides [9,10], and polyaromatic hydrocarbons (chrysene, pyrene, fluoranthene, anthracene, naphthalene etc.) [11], which all are carcinogenic and mutagenic in nature [12]. Metallic nanoparticles (NPs) have been used in the past few years, as many metals such as copper (Cu), silver (Ag), gold (Au), platinum (Pt), zinc (Zn) and titanium (Ti) show promising results once utilised in nanosized composites compared to bulk mate- rials [3]. Metallic NPs have various exceptional properties such as magnetic, electronic, Processes 2023, 11, 141. https://doi.org/10.3390/pr11010141 https://www.mdpi.com/journal/processes