In the present era, due to industrial revolution in the developing country like India, the ground water system has been largely polluted, especially with heavy metals like chromium. The removal of such heavy metals from industrial effluents and from wastewater has become a subject of keen interest. This paper deals with the removal of chromium from its aqueous solution using egg shell, a waste material as an adsorbent. Experimental results vividly demonstrate that this extraction method was found to be cheaper, quicker and more efficient than other conventional techniques. The results are interpreted in the light of Loggergren’s model.
Due to gradual depletion of world petroleum reserves and the impact of environmental pollution of increasing exhaust emissions, there is an urgent need for suitable alternative fuels for use in engines. The heightened awareness of green house gas emissions and global warming compels introduction of more stringent environmental regulations worldwide. Renewable biofuels are considered potential solution for these problems. But use of biofuel is creating tribology related new challenges world over. In this paper a critical analysis of tribology related issue of three main biofuels, namely Straight Vegetable Oil (SVO), biodiesel and alcohols are discussed. Many issues like lubricity of blends, carbon deposit, viscosity, corrosion of engine components, etc are discussed in detail. Quality control of biofuels, identified as a key factor for sustainable market growth of these fuels and can lead to many tribological issues. In this regard a dire need for global harmonized standards is also discussed. Different solutions for alcohol fuel related engine problems are discussed. Critical discussion in relation to the problems due to the use of SVO in engine, like engine performance decrease, injector choking, oil ring sticking, etc took place in this paper. Potential solutions to these problems found by academia as well as industry are discussed here.