Gaikwad -Gupta: Review on removal of heavy metals from acid mine drainage - Abstract. Acid mine drainage (AMD) is one of the most significant environmental challenges facing the mining industry worldwide.This article summarizes the literature on the removal of heavy metals from acid mine drainage wastewater by various techniques. Investigation has been carried out across the world in order to control and decrease the level of heavy metals as pollutants from acid mine drainage wastewater.

Activated carbon has been widely used as a good adsorbent. Water hyacinth may be an alternative of activated carbon. This work deals with the study of methylene blue adsorption on activated carbon as well as water hyacinth ash from aqueous solution. Batch kinetic and isotherm studies were carried out at different conditions like, contact time, methylene blue concentration etc for both adsorbents. The Freundlich and Langmuir adsorption models have been mathematical description of adsorption equilibrium and finally it has been that observed that the experimental data fitted more accurate to the Langmuir model for both cases.

Sugar cane bagasse ash, an agricultural byproduct, acts as an effective adsorbent for the removal of dyes from aqueous solution. Batch adsorption study was investigated for the removal of Acid Orange-II from aqueous solution. Adsorbents are very efficient in decolorized diluted solution. The effects of bed depth on breakthrough curve, effects of flow rate on breakthrough curve were investigated. The removal of dyes at different flow rate (contact time), bed height, initial dye concentration, column diameter, pH & temperature by Sugarcane Bagasse Ash as an adsorbent has been studied. It is found that percent adsorption of dyes increases by decreasing flow rate from 2 lit/hr to 1 lit/hr, by increasing bed height from 15cm to 45cm, by decreasing initial conc.150mg/lit to 100mg/lit, by increasing column diameter from 2.54cm to 3.5cm,by maintaining neutral pH & at temperature 45ºc than 25ºc & 35ºc.The result shows that, bagasse ash is a good adsorbent for dye effluent treatment.

Superparamagnetic iron oxide nanoparticles (SPIONs), due to their controllable sizes, relatively long in vivo half-life and limited agglomeration, are ideal for biomedical applications such as magnetic labeling, hyperthermia cancer treatment, targeted drug delivery and for magnetic resonance imaging (MRI) as contrast enhancement agents. In order to understand how SPIONs interact with cells and cellular membranes it would be of interest to characterize individual SPIONs at the nanoscale in physiologically relevant conditions without labeling them. We demonstrate that Magnetic Force Microscopy (MFM) can be used to image SPIONs in air as well as in liquid. The magnetic properties of bare and SiO 2 coated SPIONs are compared using MFM. We report that surface modification using (3-mercaptopropyl)-trimethoxysilane significantly improves adsorption and distribution of SPIONs on gold surfaces. To obtain proof of principle that SPIONS can be imaged with MFM inside the cell we imaged SPIONs buried in thin polymer films (polystyrene (PS) and poly methyl-methacrylate (PMMA)). This opens the possibility of visualizing SPIONs inside the cell without any labeling or modifications and present MFM as a potential magnetic analogue for fluorescence microscopy. The results of these studies may have a valuable impact for characterization and further development of biomedical applications of SPIONs and other magnetic nanoparticles.Keywords: Magnetic force microscopy (MFM) imaging in liquid; superparamagnetic iron oxide nanoparticles (SPIONs); magnetic properties; surface modification for nanoparticle adsorption; silica coated SPIONs; MFM imaging of SPIONs in liquid and inside polymer films

The mining industry faces stringent effluent discharge regulations and has acknowledged that it is necessary to look into innovative technologies to recycle considerable amount of effluent rather than discharging into surface water. Effluents from mines give rise to aesthetic unpleasantness. The focus of the investigations was to cope with more stringent effluent discharge regulations and to protect the ecosystem from harmful pollutants in the mine effluents. Copper is one of the heavy metal in the mine systems, which are known to be a harmful element. The present study has been undertaken to investigate a process that might remove Cu(II) from mine waste water by using natural zeolite, such as stilbite, and compared with synthetic resins like CSA-9 and CSA-609D. In this study, natural zeolite was used as a low-cost adsorbent to evaluate its ability to remove heavy metals from acid mine drainage. The zeolite used in this study is the natural clay mineral from the Nizarneshwar Hills of Western India. Three resins tested are CSA-9, natural zeolite-stilbite, and CSA-609D. Batch testing has been conducted to select effective ionexchange resins for copper removal and to determine effective regenerants for regeneration of exhausted resins. All tests were conducted at bench scale and in batch mode.Three strong acid cation exchangers were evaluated to compare their metal removal capacities. The metal concentration in the effluent was reduced with all resins tested. It was found that, among all the three types of natural zeolite, stilbite shows the highest removal efficiency of copper in every parameter that is considered for evaluating the performance of resins.