Indian Institute of Technology Roorkee

Abstract: Dyes are an important class of pollutants, and can even be identified by the human eye. Disposal of dyes in precious water resources must be avoided, however, and for that various treatment technologies are in use. Among various methods adsorption occupies a prominent place in dye removal. The growing demand for efficient and low-cost treatment methods and the importance of adsorption has given rise to low-cost alternative adsorbents (LCAs). This review highlights and provides an overview of these LCAs comprising natural, industrial as well as synthetic materials/wastes and their application for dyes removal. In addition, various other methods used for dye removal from water and wastewater are also complied in brief. From a comprehensive literature review, it was found that some LCAs, in addition to having wide availability, have fast kinetics and appreciable adsorption capacities too. Advantages and disadvantages of adsorbents, favourable conditions for particular adsorbate-adsorbent systems, and adsorption capacities of various low-cost adsorbents and commercial activated carbons as available in the literature are presented. Conclusions have been drawn from the literature reviewed, and suggestions for future research are proposed.

Abstract: The global population is increasing and because of this, the world may experience great fresh water scarcity. Our water resources are limited and, hence, water treatment and recycling methods are the only alternatives for getting fresh water in the coming decades. Therefore, there is a great need for the development of a suitable, inexpensive and rapid wastewater treatment techniques and reuse or conservation methods in the present century. The different types of water treatment and recycling techniques have been discussed in terms of their basic principles, applications, costs, maintenance and suitability. Additionally, a systematic approach to water treatment and recycling involving their understanding, evaluation and selection parameters has been presented. A brief guideline for the selection of the appropriate technologies for specific applications has been evaluated. This review adds to the global discussions on water scarcity solutions.

Abstract: Many Schiff base complexes of metal ions show high catalytic activity. Chiral Schiff base complexes are more selective in various reactions such as oxidation, hydroxylation, aldol condensation and epoxidation. The catalytic activity of metal complexes of binaphthyl, binaphthol and their combinations with salen Schiff base is presented in this review. The pyridyl bis(imide) and pyridine bis(imine) complexes of cobalt(II), iron(II) ions have been used as catalysts in the polymerization of ethylene and propylene. The phenoxy-imine (FI) complexes of zirconium, titanium and vanadium and Schiff base complexes of nickel(II) and palladium(II) were also used as catalysts in the polymerization of ethylene. Schiff base complexes of metal ions were catalytic in ring opening polymerization processes at low temperature. Schiff base complexes also catalyzed the oxidation of sulfides, thioanisoles, aldehydes, phenol and styrene. Schiff base complexes in super critical carbon dioxide (ScCO2) and in the presence of polar solvents were active catalysts. Schiff base complexes showed significant activity in catalyzing allylic alkylations, hydrosilation, the decomposition of hydrogen peroxide, isomerization, and annulation and carbonylation reactions. The high thermal and moisture stabilities of many Schiff base complexes were useful attributes for their application as catalysts in reactions involving at high temperature.

Abstract: Among various water purification and recycling technologies, adsorption is a fast, inexpensive and universal method. The development of low-cost adsorbents has led to the rapid growth of research interests in this field. The present protocol describes salient features of adsorption and details experimental methodologies for the development and characterization of low-cost adsorbents, water treatment and recycling using adsorption technology including batch processes and column operations. The protocol describes the development of inexpensive adsorbents from waste materials, which takes only 1-2 days, and an adsorption process taking 15-120 min for the removal of pollutants. The applications of batch and column processes are discussed, along with suggestions to make this technology more popular and applicable.

Abstract: The world is confronted with the twin crises of fossil fuel depletion and environmental degradation. The indiscriminate extraction and consumption of fossil fuels have led to a reduction in petroleum reserves. Alternative fuels, energy conservation and management, energy efficiency and environmental protection have become important in recent years. The increasing import bill has necessitated the search for liquid fuels as an alternative to diesel, which is being used in large quantities in transport, agriculture, industrial, commercial and domestic sectors. Biodiesel obtained from vegetable oils has been considered a promising option. In this paper, an attempt has been made to review the work done on biodiesel production and utilization, resources available, process(es) developed/being developed, performance in existing engines, environmental considerations, the economic aspect, and advantages in and barriers to the use of biodiesel.