M. H. Fulekar

Microbial decolorization and degradation of synthetic dyes: a review

The synthesis of dyes and pigments used in textiles and other industries generate the hazardous wastes. A dye is used to impart color to materials of which it becomes an integral part. The waste generated during the process and operation of the dyes commonly found to contain the inorganic and organic contaminant leading to the hazard to ecosystem and biodiversity causing impact on the environment. The amount of azo dyes concentration present in wastewater varied from lower to higher concentration that lead to color dye effluent causing toxicity to biological ecosystem. The physico-chemical treatment does not remove the color and dye compound concentration. The decolorization of the dye takes place either by adsorption on the microbial biomass or biodegradation by the cells. Bioremediation takes place by anaerobic and/or aerobic process. The anaerobic process converts dye in toxic amino compounds which on further treatment with aerobic reaction convert the intermediate into CO2 biomass and inorganics. In the present review the decolorization and degradation of azo dyes by fungi, algae, yeast and bacteria have been cited along with the anaerobic to aerobic treatment processes. The factors affecting decolorization and biodegradation of azo dye compounds such as pH, temperature, dye concentration, effects of CO2 and Nitrogen, agitation, effect of dye structure, electron donor and enzymes involved in microbial decolorization of azo dyes have been discussed. This paper will have the application for the decolorization and degradation of azo dye compound into environmental friendly compounds.

Environment and sustainable development

Preface.- Contributors.- 1.Emergence of Green Technologies towards Sustainable Growth.- 2.Sustainable Development: An Earnest Hope.- 3.Soil Seed Bank Dynamics: History and Ecological Significance in Sustainability of Different Ecosystems.- 4.Challenges and Prospects in Exploring Marine Microbial Diversity.- 5.Bioprospecting of Plant Essential Oils for Medicinal Uses.- 6.Air Pollution Scenario over Delhi City.- 7.Nanotechnology: Perspectives for Environmental Sustainability.- 8. An Overview of Environmental Remediation using Photocatalyst.- 9.Role of Biopolymers in Industries: their prospective future applications.- 10.Green Federalism: A Historical leap towards Sustainable Human Development.- 11.Economic sustainability in light of consumer behavior: Social Perspectives.- 12.Global warming and agriculture: Industrial Arrangement for sustainable Development.- 13.Green Buildings - Opportunities and Challenges.- 14. Mathematical models in sustainable development.- Index.

Ag incorporated nano BiPO4: sonochemical synthesis, characterization and improved visible light photocatalytic properties

We report an efficient route for the sonochemical synthesis of undoped BiPO4, Ag3PO4 and silver doped BiPO4:Ag(x%) (x = 2, 5, 10 and 20) nanostructures using bismuth/silver nitrate and ammonium dihydrogen phosphate as precursors. The products obtained have been characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (UV-vis DRS) and X-ray photoelectron spectroscopy (XPS). The size and morphology of BiPO4 exhibited drastic changes on Ag doping. The surface areas of the samples have been estimated using the Brunauer–Emmett–Teller (BET) method. The catalytic activities of all the samples for the rhodamine-B degradation were investigated systematically under UV and visible-light irradiation. Undoped BiPO4 exhibited excellent photocatalytic activity under UV light but the degradation of RhB was only ∼60% under visible light, while Ag doped BiPO4 samples showed almost complete degradation of the dye under visible light. Amongst all of them, BiPO4:Ag(10%) exhibited the best photocatalytic activity. Furthermore, after photocatalysis, the nanoparticles could be readily separated from the reaction system by low-speed centrifugation and reused. Stability of the photocatalysts was ascertained using FT-IR and Raman spectroscopy. After five recycles, the nanoparticles did not exhibit any apparent loss in activity, confirming its stability despite recycling. By tuning the band gap and measuring the surface area of the nanoparticles using BET tests, we found that the combined effect of these two factors resulted in good performance of the BiPO4:Ag(10%) photocatalyst under visible light irradiation.

Molecular approaches for biodegradation of polycyclic aromatic hydrocarbon compounds: a review

The waste generated from industrial processes and operations including domestic wastes when treated partially and disposed in soil–water environment enter to lakes, streams, rivers, oceans and other water bodies. The pollutants get dissolved or lie suspended in water or get deposited on soil sediment beds. This results on aquatic and terrestrial pollution which ultimately impact ecosystems causing toxicity to biota and human beings. Industries such as petrochemical, pharmaceutical, insecticides and fertilizers generates the hazardous waste comprising of inorganic and organic compounds. Organic compounds mainly composed polycyclic aromatic hydrocarbons (PAHs), are one of the toxic environmental pollutant. This paper highlights the physicochemical properties, bioremediation treatment and its mechanism for the waste containing PAH. The process of biological remediation depends upon the metabolic action of microbe toward the contaminant which can be achieved by optimum water and nutrient supply and some other limiting factors. The enzymatic degradation gives the molecular approaches for bioremediation. The study also highlighted the molecular approaches which are helpful in revealing functional, structural and communal information about microbial diversity for exploring the routes of degradation pathway of bioremediation process and future scope to bioremediation of PAHs.

Biosynthesis of titanium dioxide nanoparticles using Bacillus amyloliquefaciens culture and enhancement of its photocatalytic activity for the degradation of a sulfonated textile dye Reactive Red 31

The present study aims at exploiting Bacillus amyloliquefaciens for the biosynthesis of titanium dioxide nanoparticles and also investigates role of bacterial enzymes in the biosynthesis of titanium dioxide nanoparticles. Bacterial synthesized as well as metal doped titanium dioxide nanoparticles were characterized by X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), Energy dispersive X-ray spectroscopy (EDAX). Amylase activity (43.37IU) in culture supernatant evinced a potential involvement of extracellular enzyme in TiO2 nanoparticle biosynthesis. Crystallite size of bio-synthesized nanoparticles was found to be in the range of 15.23-87.6nm. FTIR spectroscopy and native-PAGE (Polyacrylamide Gel Electrophoresis) clearly indicated involvement of alpha amylase in biosynthesis of TiO2 nanoparticles and in their stabilization. TEM micrographs of the synthesized titanium dioxide nanoparticles revealed the formation of spherical nanoparticles with a size range of 22.11-97.28nm. Photocatalytic degradation of Reactive Red 31 (RR31) dye was carried out using bio-synthesized TiO2 nanoparticles under UV radiation. Photocatalytic activity of synthesized nanoparticles was enhanced by Ag, La, Zn and Pt doping. Platinum doped TiO2 showed highest potential (90.98%) in RR31 degradation as compared to undoped (75.83%).

Nanotechnology: Perspective for Environmental Sustainability

“Environmental nanotechnology” is considered to play a key role in the shaping of current environmental engineering and science. The conventional environmental remedial techniques seem to be relatively ineffectual in the face of currently extensively expanding load of pollutants that permeate the air, water, and soil environment. Nanotechnology can provide a way to purify the air and water resources by utilizing nanoparticles as a catalyst and/or sensing systems. In the present research chapter, the potential of nanotechnological products and processes and their application to clean up the environment contaminants have been discussed. Water treatment and purification techniques based on nanotechnology have been highlighted. These also include the environmental and energy application of nanotechnology which focuses on clean technology, reducing global warming, eco-friendly and efficient energy-generating techniques, eco-friendly surface coating, remediation techniques, and environmental monitoring. Environmental nanoscience products, devices, and processes have an impact on socioeconomic aspects for maintaining a clean environment for sustainable development.

Bioremediation of Organic Pollutants Using Phanerochaete chrysosporium

Phanerochaete chrysosporium—white rot fungus—has been reported as an effective for bioremediation of different hazardous compounds. In this chapter, the life cycle of white rot fungus and the conditions required for its growth so as to make effective bioremediation of compounds have been cited. The research study carried out by the scientists for the bioremediation of polycyclic aromatic hydrocarbons (PAHs), contaminated soils, and other compounds has been highlighted as research case studies. The mechanism of bioremediation of different compounds with respect to use of white rot fungus has also been cited. Therefore, the use of white rot fungus for the biodegradation of the hazardous compounds will benefit to decontaminate the environment, and this technology can be adapted as a remedial measure for treatment of hazardous wastes.

Photocatalytic degradation of organophosphate pesticides (Chlorpyrifos) using synthesized zinc oxide nanoparticle by membrane filtration reactor under UV irradiation

NanomaterialZinc oxide (ZnO) has been synthesized using Zinc Nitrate Hexahydrate as precursor by Sonochemical Method. The as-synthesized ZnO was characterized to study their optical, morphological and physical properties. Fourier Transform-Infra Red Spectroscopy analysis was done for identification of functional group, Scanning Electron MicroscopyEnergy Dispersive X-Ray Analysis for Morphology and Size and elemental confirmation, Transmission Electron Microscopy for determination of particle size and shape and X-Ray Diffraction for the identification of crystal structure. The material developed was used in a membrane filtration technology for degradation of selected pesticide. Pesticides(Chlorpyrifos) taken at fixed concentration (5 ppm) in a solvent and then stimulated effluents were subjected to photocatalytic degradation and allow to pass through the membrane filtration assembly under low pressure using cellulose acetate mixed polymeric membrane discs. Samples were analyzed by UV-VIS spectroscopy for the assessment of degradation of Chlorpyrifos. Results shows that ZnO alone show low degradation efficiency as compared to membrane filtration. When combined both the approaches (ZnO + Membrane filtration) there is steep decline in the absorption peak. Nanobased membrane filtration technology design and developed were found effective and efficient for the degradation of pesticides as compared to photocatalytic degradation carried out using ZnO.

Photocatalytic degradation of a textile dye Reactive Red 31 using phyto-synthesized titanium nanoparticles under solar irradiation

AbstractIn the present work, we have reported a sustainable and effective method for the degradation of a textile dye Reactive Red 31 (RR31) using synthesized titanium nanoparticles. Titanium dioxide nanoparticles were synthesized using a noxious weed, Parthenium hysterophorus, as reducing and capping agent for the first time. The synthesized nanoparticles were characterized and confirmed as TiO2 nanoparticles by using X-ray diffraction spectroscopy, Fourier transformation infrared spectroscopy, and scanning electron microscopy analysis. A glass reactor was designed and developed for the degradation of dye under solar radiations. Photocatalytic degradation of Reactive Red 31 was carried out at different concentrations using synthesized nanoparticles. UV–vis spectroscopy, total organic carbon, and total inorganic carbon analysis were carried out for the determination of dye degradation. The results reveal that biogenic TiO2 nanomaterial acts as a good photocatalyst for the degradation of textile dye Reacti...

Biotechnological Strategies for Enhancing Phytoremediation

Phytoremediation to clean up soil or sediments contaminated with metals and other pollutant compound has gained increasing attention as environmental friendly and cost effective. Achievements of the last decade suggest that genetic engineering of plants can be instrumental in improving phytoremediation. Members of the Cruciferae plant family have a key role in phytoremediation technology. Many wild crucifer species are known to hyperaccumulate heavy metals and possess genes for resistance or tolerance to the toxic effects of a wide range of metals. Many of these species are well adapted to a range of environmental conditions. Some species are tolerant to high levels of heavy metals, and there is the potential to select superior genotypes for phytoremediation. They are well suited to genetic manipulation and in vitro culture techniques and are attractive candidates for the introduction of genes aimed at phytoremediation. The use of genetic engineering to modify plants for metal uptake, transport and sequestration may open up new avenues for enhancing efficiency of phytoremediation. Metal chelator, metallothionein, phytochelatin and metal transporter genes have been transferred to plants for improved metal uptake and sequestration in crucifers. The purpose of this article is to review different biotechnological approaches to enhance phytoremediation in crucifers.