Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 2, 2000
Publication Date: N/A
Interpretive Summary: Attrition is defined as the unwanted breakdown of a particle within a process. With adsorbents, such as ion exchange resins that are reused in various applications, attrition must be minimal over a long time period. Attrition in citric acid modified soybean hulls was determined and compared to attrition in commercial cation exchange resins. The modified hulls had been previously observed to bind metal ions such as copper as well as the commercial resins. Attrition in modified hulls was similar to attrition in the commercial products, except at high temperatures (85 deg C) and high pH (pH 11), where attrition was greater in the hulls. Our studies indicate that as far as product integrity is concerned, modified hulls could be beneficial to industries, such as metal platers, that require a reuseable, high adsorption capacity metal ion adsorbent.
Technical Abstract: Attrition in base-extracted (BE), citric acid (CA)-modified soybean hulls, a lignocellulosic cation exchange material, was compared to attrition in two commercial cation exchange resins, both synthetic polymers. Attrition was determined in both batch and column experiments. Batch studies included measuring attrition over a 24 hr period under conditions of constant pH, variable pH and at different temperatures. Under conditions of a constant pH of 4.8, 25 deg C and using a stir bar, modified hulls had mostly lower attrition than the two commercial products. Under acidic conditions, modified hulls demonstrated very low (< 5%) attrition. However, at alkaline pH values, modified hulls had higher attrition than the resins after 24 hr of stirring at 25 C. After 24 hr of shaking at temperatures of 65 deg C and 85 deg C, modified hulls also had greater attrition than the synthetic polymers. When the products were compared in column experiments, all materials had low (< 10%) attrition. Our studies indicate that as far as product integrity is concerned, modified soybean hulls could be useful in several applications requiring a metal ion adsorbent.