Indian Institute of Technology (IIT) Mandi research team has recently made headlines with an innovative approach to efficiently eliminate heavy metals from water. This breakthrough was accomplished thanks to a biopolymer-based material that assists in separating these hazardous elements from liquid samples.
Funding and Details of the Research
The study, which was generously supported by the Ministry of Mines, Government of India, resulted in the creation of a fibrous membrane filter. This unique filter contains adsorbent materials that act as a magnet, attracting and retaining the metals. The adsorbents possess a large proportion of Chitosan, a biopolymer derived from crab shells, combined with a renowned polymer, Nylon.
The Solution Blowing Process
The research team used a procedure known as “solution blowing”, unlike most fibre-based adsorbents that are produced through a method called “melt blowing”. Solution blowing starts from dissolving the polymer in solvent, such as cellulose in ionic liquid. The solution is then pumped through a spin nozzle where air is blown at high speed concentrically. This process creates fibres that are extremely fine – nanometres in diameter, offering a significantly increased surface area which results in better adsorption of heavy metals.
Advantages of the New Method
The new method provides several advantages over traditional processes. The biopolymer-based material adsorption occurs not only at the surface but also at sub-surface levels, leading to enhanced metal removal efficiency. Additionally, these membranes can be reused up to eight times before a significant reduction in metal adsorption efficiency is observed.
Moreover, the adsorbed metal can easily be recovered in a metal-hydroxyl nitrate form, adding extra value to the membrane filter. The researchers have also proposed a method for large scale production of these fibre-based adsorbents, capable of handling greater volumes of metal-contaminated water.
Environmental Impact and Efficiency
The use of the solution blowing technique could potentially replace synthetic polymers with natural polymers, contributing to a more environmentally conscious approach.
About Heavy Metals and Their Sources
Heavy metals are metallic chemical elements with a relatively high density (> 5 g/cm3) and can be toxic or poisonous at low concentrations. These metals include mercury, cadmium, arsenic, chromium, thallium, and lead. They find their way into the environment through natural phenomena or human activities. The Central Water Commission (CWC) reports that two-thirds of the water quality stations across major Indian rivers have detected heavy metal contamination beyond safe limits set by the Bureau of Indian Standards.
Heavy Metals and Human Health
While some heavy metals like cobalt, copper, zinc, and manganese are required by the human body in trace amounts, excessive exposure can be harmful. Contaminants such as lead, mercury, arsenic, and cadmium found in drinking water can accumulate in the body over time, causing severe health problems. Diseases linked to these metals include Mercury Minamata disease, Cadmium Itai Itai, Lead Anemia, Arsenic Black foot disease, and Nitrates Blue Baby Syndrome.
Last Modified: February 11, 2024