Submitted to: Corn Dry Milling Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: May 28, 1998
Publication Date: N/A
Technical Abstract: Corn products were derivatized with citric acid (CA) to enhance their metal-binding properties for potential use in wastewater treatment. CA derivatives of corn flour (CFL) were compared with derivatives from washed corn products including corn starch (CS), corn fiber (CF), corn gluten meal (CGM) along with cellulose fiber (CEL) to determine the effectiveness of the derivatization process as well as their binding properties to nine heavy metals. Except for DDG and CGM, the citrate derivatives were generated by oven heating 1:1 w/w, material/CA for 24 hr. DDG and CGM were each derivatized via a continuous high heat extrusion process. The resulting citrate derivatives from either process were finely ground and water washed to remove unreacted CA to yield acid-insoluble derivatives. Carboxyl content of these derivatives was determined via titration. Whereas, metal ion binding was performed at pH 4.5 with metal ion concentration of approx. 200 ml/L. Metal analysis was accomplished with a Perkin-Elmer Plasma 400 Emission Spectrometer. Our results showed similarities with metal-binding and carboxyl content for citrate derivatives of: CFL and CS; CF and GCC; the higher protein corn products DDG and CGM bound Pb**2+ better than all others; the high purity CEL derivative tended to give the least metal binding. With the exception of Pb**2+ binding, CFL gave best overall results. When its metal-binding ability was compared with a commercial (AG50W-X8 from Bio-Rad Laboratories, Richmond, CA), the CFL/CA derivative possessed 38-84% of the capacity to bind metals than the petroleum-based product. The corn-based derivatives produced in our study are potentially biodegradable and can be generated at a considerable cost savings when compared with petroleum-based resins.