D. V. Gupta’s scientific contributions

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 ion-exchange 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.

The removal of copper from acid mine drainage waste by ion exchange resins, such as Indion 820 and Indion 850, is investigated. Effect of initial metal ion concentration, resin dose and pH on exchange capacities of ion exchange resins was studied in a batch method. The adsorption process, which is pH dependent, shows maximum removal of copper in the pH range 2-6 for an initial copper concentration of 50-250 mg L-1 and with resin dose 25-700 mg L-1. The experimental data have been analyzed by using the Freundlich, Langmuir, Redlich-Peterson, Temkin and Dubinin-Radushkevich isotherm models. The isotherm constants for all these isotherm models have been calculated. The uptake of copper by the ion exchange resins was reversible and thus has good potential for the removal/recovery of copper from acid mine drainage wastewater. Ion exchange resins, such as Indion 820 and Indion 850 can be used for the efficient removal of copper from mine wastewater.

AMD is recognized as one of the most serious environmental problem in the mining industry. The problem of acid mine drainage (AMD) has been present since mining activity began thousands of years ago. Mining activity has disrupted the hydrology of mining areas so badly that it is extremely difficult to predict where water would eventually re-emerge. Its causes, treatment have become the focus of number of researchers. This paper describes Acid Mine Drainage (AMD) generation and its associated pollution.