The researchers prepared the mold in the study using Ganga soil from Varanasi ghat and bentonite clay.
The mold has been tested for its ability to adsorb copper, nickel and zinc ions. The adsorption process showed that equilibrium was reached within half an hour of the process.
The research is published in the International Journal of Environmental Science and Technology, published by Springer. The impact factor for this review is 3.083.
Giving background on this research, Assistant Professor Dr. Vishal Mishra, Principal Investigator of the School of Biochemical Engineering and his PhD student Jyoti Singh said that bentonite is a clay mineral from the smectite group found in nature.
It has a large active surface, specific moisturizing properties and strong cation exchange capacities. It is inexpensive, widely available, and effective against a wide range of impurities and metal ions. Because of these properties, bentonite clay is an excellent choice for the removal of heavy metal ions from bulk solutions. One of its interesting properties is the ability of bentonite to adsorb cations.
He further explained that adsorption in soil occurs when components in solution adsorb on the surface of soil particles. This process is influenced by the inorganic and organic components of the soil surface as well as the associated environmental conditions.
Soil particles can include a wide variety of compounds, including soil components, plant nutrients, surfactants, pesticides, and environmental pollutants found in soil solutions.
Soil is amphoteric, with a broad spectrum of negative and positive charges and magnitudes. Clay retains a stable negative charge due to ion substitution or site vacancies in crystalline clay minerals and structural defects due to non-crystalline hydrated oxides of silica, iron and aluminum.
Dr. Vishal Mishra informed that Varanasi has a humid subtropical climate with significant temperature difference between summer and winter. The average annual rainfall in the basin varies from 39 to 200 cm, with an average of 110 cm. Eighty percent of the rainfall occurs during the monsoon season, which lasts from June to October.
Due to the large temporal variation in precipitation throughout the year, the flow characteristics of the river vary considerably. Concentrations of all heavy metals (Cd, Cr, Cu, Ni and Pb) increased at downstream sampling stations.
The main sources of these elements are emissions from nearby urban and industrial areas. Vehicle emissions are the main source of urban particles. Re-suspension of particles deposited on the ground can provide further evidence of heavy metal loading.
He said heavy metals have high atomic numbers, atomic weights and atomic densities and are poisonous if consumed in large amounts.
Although heavy metal poisoning is generally treatable, prolonged exposure can lead to life-threatening and debilitating illnesses.