In recent years, the application of heterogeneous photocatalytic water purification process has gained wide attention due to its effectiveness in degrading and mineralizing the recalcitrant organic compounds as well as the possibility of utilizing the solar UV and visible light spectrum. This paper aims to review and summarize the recently published works on the titanium dioxide (TiO2) photocatalytic oxidation of pesticides and phenolic compounds, predominant in storm and waste water effluents. The effect of various operating parameters on the photocatalytic degradation of pesticides and phenols are discussed. Results reported here suggested that the photocatalytic degradation of organic compounds depends on the type of photocatalyst and composition, light intensity, initial substrate concentration, amount of catalyst, pH of the reaction medium, ionic components in water, solvent types, oxidizing agents/electron acceptors, catalyst application mode, and calcinations temperature in water environment. A substantial amount of research has focused on the enhancement of TiO2 photocatalysis by modification with metal, non-metal and ion doping. Recent developments in TiO2 photocatalysis for the degradation of various pesticides and phenols are also highlighted in this review. It is evident from the literature survey that photocatalysis has shown good potential for the removal of various organic pollutants. However, still there is a need to find out the practical utility of this technique on commercial scale.

Influence of parameters on the heterogeneous photocatalytic degradation of pesticides and phenolic contaminants in wastewater : a short review

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

Collective removal of phenol and ammonia in a moving bed biofilm reactor using modified bio-carriers: Process optimization and kinetic study.

The enigma of aerobic vs. anaerobic decomposition in marine sediments was addressed by means of a thin-layer incubation technique. Two different 14C-labeled plant materials, aged diatoms (Skeletonema costatum) and fresh barley hay, were each mixed into intertidal sediment and spread in a 1.5-mm layer on the bottom of oxic and anoxic chambers. After a 27-d incubation, conditions in all chambers were switched from aerobic to anaerobic and vice versa for 11 d. Rates of 14C0, evolution in diatom chambers showed that aerobic carbon mineralization was - 10 times faster than anaerobic both before and after the switch. Low rates of [14C]DOC release suggested that the limiting step of an,aerobic decay was the initial hydrolytic and fermentative enzymatic attack on the predecomposed diatoms. Initial carbon mineralization of barley hay was not affected by the presence or absence of oxygen. Leaching of DOC from the fresh barley hay supplied anaerobic respirers with labile substrates. When leaching ceased and after the aerobic-anaerobic switch, the rate of anaerobic mineralization was reduced. Mineralizat:.on of leachable and easily hydrolyzable compounds from fresh plant detritus is equally fast under aerobic ant! anaerobic conditions. When structural components dominate the particulate remains, anaerobic processes are hampered by inefficient and slow bacterial hydrolysis of structurally complex macromolecules.

Aerobic and anaerobic decomposition of organic matter in marine sediment: which is fastest?

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

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

This study evaluated the capability of Serratia marcescens ABHI001 to effectively degrade p-cresol through different techniques. The molecular identity of the laboratory isolate S. marcescens ABHI001 was confirmed through the 16S ribosomal DNA gene pattern, and its morphological features were investigated through field-emission scanning electron microscopy. In addition, the degradation behavior of the isolate for cresol was verified using several techniques, including UV–visible spectroscopy, followed by high-performance liquid chromatography (HPLC), gas chromatography, and Fourier transform infrared spectroscopy. The maximum degradation percentage of 85% for p-cresol could be achieved after 18 h of incubation with S. marcescens ABHI001. The formation of p-hydroxybenzaldehyde, p-hydroxybenzoate, and protocatechuate metabolites was confirmed through HPLC. The study results indicate that S. marcescens ABHI001 may have applications in the bioremediation of organic pollutants, such as p-cresol.

Analytical study of effective biodegradation of p-cresol using Serratia marcescens ABHI001: application in bioremediation

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.

A. K. Bhatiya

Papers

Application of TiO2 Nanoparticle in Photocatalytic Degradation of Organic Pollutants

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

Analytical study of effective biodegradation of p-cresol using Serratia marcescens ABHI001: application in bioremediation

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