Spent Grain Adsorbent Material for Heavy Metals

Conventional wastewater treatment technologies are not able to provide low-cost and effective removal of heavy metals from wastewater. Adsorption processes using agricultural byproducts can potentially provide a low- cost solution, but the adsorption capacity needs to be improved.

The 360ip Partner’s invention relates to the production and use of esterified spent grain (ESG) as an adsorption material for the removal of heavy metals in wastewater. Spent grain is a common byproduct in the beer industry, and is usually not fully usable as animal feed, potentially creating a costly disposal problem.

The novel process of creating the ESG involves the use of citric acid as esterifying agent, NaH2PO-2•H2O as catalyst and N, N-dimethylformamide (DMF) as reaction medium to create an ESG with high adsorption capacity for heavy metal ions. The use of DMF also serves as a swelling agent that can enhance the reaction activity and shorten the process time.

The key advantages associated with this technology are as follows:

Low-cost process using easily available spent grain material

Short processing time for production of the ESG

High adsorption capacity, superior to ion-exchange resin

ESG can be desorbed and reused at least three times