Removal of cadmium in wastewater through geopolymeric materials based on pumice.

Heavy metal pollution in the effluent water due to industrial waste product of various economic activities is not adequately regulated in Colombia, this is because the agencies do little control track discharge and easily granting environmental licenses. As a result of this little regulation currently they do not have updated figures that provide real information on the amount of waste that ends up in the resort, causing health effects of living beings. In the tanning industry, in particular, there cadmium residual concentration higher than the maximum allowed by the Ministry of the environment. This work considers the use of a geopolymeric material based on pumice stone, to capture cadmium ions present in wastewater and thus reduce its concentration in the water resource in order to reduce the population's exposure to diseases that are associated with accumulation of cadmium in the body. The synthesis of geopolymer began from the alkaline activation of pumice stone with commercial sodium silicate, the use of sand:pumice stone in a 1:1 ratio and 31 hours of reaction, these proportions were defined in a previously work by the authors. The morphological and crystallographic characterization of the sorbent geopolymeric material was performed by scanning electron microscopy and X-ray diffraction. To assess the sorption process, a study of the geopolymer's contact time with a known solution of cadmium was performed. Cadmium concentration was determined using atomic absorption spectroscopy and the geopolymer was characterized after removal.