Green approaches in synthesising nanomaterials for environmental nanobioremediation: Technological advancements, applications, benefits and challenges.

Background: Nanotechnology is the branch of science and technology, which deals with the production of substances in size less than100nm scale as nanoparticles. Nanoparticles are studied as building blocks of the next generation of technology with applications in different disciplines. Currently biological species like algae are in great use for the nanoparticles synthesis. Algae are ecological and economically important eukaryotic, photosynthetic organism of the kingdom Protista. As like true plants, algae are not differentiated into root, stem and leaves but similar to lower plants for example Mosses, liverworts, etc. Aims: In the present study we use the extract of green alga Botryococcus braunii for the synthesis of copper and silver nanoparticles. Methods: Green alga was collected from Udaisagar Lake Udaipur (Rajasthan, India) and isolated by serial dilution method and grown on Chu-13 nutrient medium. The characterization of alga synthesized copper and silver nanoparticles was carried out by using UVVis spectroscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron spectroscopy (SEM). Green synthesized nanoparticles were toxic against bacteria and fungus. Expected findings: FT-IR measurements showed all functional groups having control over reduction and stabilization of the nanoparticles. X-ray diffraction pattern revealed that the particles were crystalline in nature with face-centred cubic (FCC) geometry. SEM micrographs have shown the morphology of biogenically synthesized metal nanoparticles. Further these biosynthesized nanoparticles were found to be highly toxic against two Gram negative bacterial strains Pseudomonas aeruginosa (MTCC 441), and Escherichia coli (MTCC 442), two Gram positive bacterial strains Klebsiella pneumoniae (MTCC 109) and Staphylococcus aureus (MTCC 96) and a fungal strain Fusarium oxysporum (MTCC 2087).

https://www.longdom.org/open-access/biogenic-synthesis-of-copper-and-silver-nanoparticles-using-green-alga-botrycoccus-braunii-and-its-antimicrobial-activit.pdf

Biogenic synthesis of copper and silver nanoparticles using Green Alga Botrycoccus braunii and its antimicrobial activity

Solvothermal synthesis of P25/Bi 2 WO 6 nanocomposite photocatalyst and photocatalytic degradation of ethylene under visible light

ZnO/PES composite membranes were fabricated by phase inversion method using DMAc as a solvent. The structure of ZnO was investigated using TEM, SEM, XRD, and TGA. TEM images of ZnO nanoparticles were well-defined, small, and spherically shaped with agglomerated nanoparticles particles of 50 nm. The SEM and XRD results were an indication that ZnO nanoparticles were present in the prepared ZnO/PES composites membranes. Contact angle measurements were used to investigate surface structures of the composite membranes. The amount of ZnO nanoparticles on PES membranes was varied to obtain the optimal performance of the composite membranes in terms of pure water flux, flux recovery, and fouling resistance using the protein bovine serum albumin (BSA) as a model organic foulant. The results showed that addition of ZnO to PES membranes improved the hydrophilicity, permeation, and fouling resistance properties of the membranes. Pure water flux increased from a low of 250 L/m2h for the neat membrane to a high of 410 L/m2h for the composite membranes. A high flux recovery of 80–94% was obtained for the composite membranes. The optimal performance of the composite membranes was obtained at 1.5 wt% of ZnO.

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Fabrication and Assessment of ZnO Modified Polyethersulfone Membranes for Fouling Reduction of Bovine Serum Albumin

The presence of toxic organic compounds in water because of the continuous practice of industrial effluents has led to the global need for generation of new, improved, advanced, and sound technologies to address the challenges of water quality. Effluents released from petrochemical refineries generate various wastes that cause water pollution and exert adverse effects because of their harmful properties such as carcinogenicity and mutagenicity. Phenols and their derivatives are common potential water pollutants and comprise a wide range of organic chemicals exhibiting poisonous characteristics. In this series, cresols are one of the types of phenols that are also considered as highly toxic pollutant because of carcinogen effect on environmental surroundings and human health issues. Therefore, it is imperative that the levels of phenols in wastewater must be reduced before discharge into the environment. Henceforth, the current chapter based on effective biodegradation and photodegradation method as well as related technologies for the remediation of organic pollutants from wastewater.

An effective approach for the degradation of phenolic waste: phenols and cresols

Heavy industrialization, specifically in the developing countries, has generated several unwanted environmental pollution. A variety of toxic organic compounds is produced in chemical and petroleum industries, which have resulted in collectively hazardous effects on the environment that needs immediate attention for remediation. Degradation of these pollutants has been tried through the various mechanism, out of which photocatalytic degradation seems to be one of the most promising approaches to reduce environmental pollution specifically in waste water treatment. Photocatalytic degradation has potential for the effective decomposition of organic pollutants due to efficiency to convert light energy into chemical energy. Additionally, the photocatalytic oxidation process is an advanced technique as it offers high degradation and effective mineralization at moderate temperature and specific radiation wavelength. Among various known photocatalysts, TiO2 is regarded as the one of the potential photocatalysts because of its hydrophilic property, high reactivity, reduced toxicity, chemical stability and lower costs. Therefore, the present chapter focuses on the role of TiO2 as the photocatalyst for the degradation of organic pollutants. The general mechanism of degradation of organic pollutants along with properties of TiO2 as the photocatalyst, existing mechanism of degradation via TiO2 was explained. The possible approaches to enhance degradation via TiO2 nanoparticle along with existing bottlenecks have been also discussed.

Application of TiO2 Nanoparticle in Photocatalytic Degradation of Organic Pollutants

Nanotechnology is a novel and rising technology with various current and potential applications. It deals with tweaking of matter in order for any of its single dimensions to drop in the nanometer volume range (1–100 nm). Among the varied methods employed for the formation of nanoparticles, the green synthesis mode offers a quick metallic nanoparticle synthesis with a simple, an economical, and an environment-friendly method having a reproducible approach. Green synthesis utilizes reducing as well as stabilizing agents from plants and other natural resources in order to fabricate nanomaterials. Due to the large extent of toxic chemicals and severe surroundings employed within the physical as well as chemical methods, biological techniques have been executed via bacteria, fungi, algae, plants, and agricultural wastes for the production of nanoparticles. Therefore, this chapter attempts to review the current information about the biological entities that are used to make greener, safer, and also environmentally sustainable nano-synthesis routes.

Tripti Singh

Papers

Application of TiO2 Nanoparticle in Photocatalytic Degradation of Organic Pollutants

Analysis of Various Green Methods to Synthesize Nanomaterials: An Eco-Friendly Approach