Nanoremediation: Nanomaterials and Nanotechnologies for Environmental Cleanup

Different global events such as industrial development and the population increment have triggered the presence and persistence of several organic and inorganic contaminants, representing a risk for the environment and human health. Consequently, the search and application of novel technologies for alleviating the challenge of environmental pollution are urgent. Nanotechnology is an emerging science that could be employed in different fields. In particular, Nanoremediation is a promising strategy defined as the engineered materials employed to clean up the environment, is an effective, rapid, and efficient technology to deal with persistent compounds such as pesticides, chlorinated solvents, halogenated chemicals, or heavy metals. Furthermore, nanoremediation is a sustainable alternative to eliminate emerging pollutants such as pharmaceutics or personal care products. Due to the variety of nanomaterials and their versatility, they could be employed in water, soil, or air media. This review provides an overview of the application of nanomaterials for media remediation. It analyzes the state of the art of different nanomaterials such as metal, carbon, polymer, and silica employed for water, soil, and air remediation.

BIOCHAR PRODUCTION FROM WASTE BIOMASS: CHARACTERIZATION AND EVALUATION FOR AGRONOMIC AND ENVIRONMENTAL APPLICATIONS

This study focused on the valorization of different types of waste biomass through biochar production at two pyrolysis temperatures (400 and 600°C). The different feedstocks being used included three materials of municipal origin, specifically two types of sewage sludge and the organic fraction of municipal solid waste, and three materials of agroindustrial origin, specifically grape pomace, rice husks and exhausted olive pomace. The scope of the research was to characterize the resulting materials, in order to evaluate their possible uses in agronomic and environmental applications. Biochar characterization included the determination of several physical and chemical parameters, while germination assays were also carried out. Under the investigated conditions, both pyrolysis temperature and feedstock type appeared to significantly affect biochar characteristics, leading to the production of versatile materials, with many different possible uses. Specifically, results implied that biochars of both municipal and agroindustrial origin have the potential to effectively be used in applications including the improvement of soil characteristics, carbon sequestration, the removal of organic and inorganic contaminants from aqueous media, and the remediation of contaminated soil, with the degree of suitability of each material to each specific use being estimated to differ depending on its particular characteristics. For this reason, with these characteristics in mind, before proceeding to larger scale applications a cautious selection of materials should be conducted.

Cellulose-g-tetraethylenepentamine Dual-function Imprinted Polymers Selectively and Effectively Adsorb and Remove 4-Nitrophenol and Cr(VI)

A cellulosic material could efficiently and selectively adsorb organic and inorganic contaminants from aqueous solutions without interference from competing adsorption sites. In this study, cellulose-graft-tetraethylenepentamin molecular imprinted polymer (C-TEPA-MIP) was synthesized by using 4-nitrophenol (4-NP) as the template. The C-TEPA-MIP adsorbent could adsorb 4-NP and Cr(VI) simultaneously and selectively, without being affected by the competitive adsorption sites of each of these pollutants. The adsorption of 4-NP was predominantly due to the imprinted sites of 4-NP in C-TEPA-MIP that were located inside of the adsorbent, whereas that of Cr(VI) was primarily due to the amine groups of TEPA found on the surface of the adsorbent. Compared with the non-imprint polymer synthesized without the template, C-TEPA-MIP showed higher selectivity for both 4-NP and Cr(VI) in unitary and binary systems. In addition, C-TEPA-MIP exhibited good stability and recyclability for 4-NP, which makes it a promising candidate material for applications concerning wastewater treatment.

BIOREMEDIATION OF CHROMIUM (VI) BY A MICROBIAL CONSORTIUM ISOLATED FROM TANNERY EFFLUENTS AND THEIR POTENTIAL INDUSTRIAL APPLICATION

West Bengal has several leather industries and as such huge amount of leather are processed every year. The tannery effluents are discharged into the land and open water causing soil and water pollution respectively. Chromium is one of the most toxic inorganic contaminants which is well known for its carcinogenicity. Thus, our study focuses on investigating the bioremediation potential of common microflora isolated from tannery wastewater. In our study, Isolate 1 has the highest ability to reduce chromium (Cr6+) as compared to others. Isolate 4 has the highest protease, lipase and leather degradation activities. Isolate 1 shows the maximum keratinase activity making it an effective strain for keratinase production. Also, it has been found that pH 8 and temperature 40 °C was most suitable for keratinase production. Owing to the multidimensional ability of these two isolates, they were identified by 16S rRNA sequencing and it reveals that Isolate 1 and Isolate 4 belong to Bacillus cereus F4810/72 and Brevibacillus brevis F4810/72 respectively. Thus, this study establishes the role and efficiencies of these microorganisms in combatting pollution, particularly in the water bodies in which harmful chemicals leak regularly owing to improper waste management by various industries.