New metal-binding ethyldiamino- and dicarboxy-products from Aspergillus niger industrial wastes

The metal-binding ability of Aspergillus niger mycelial waste was improved by chemical modification. The latter was performed by introducing additional carboxy groups using oxidation methods or the introduction of the ethyldiamino group first by chlorination of A. niger using mesyl chloride and subsequent reaction of the product with ethylene diamine. Metal binding abilities of the products for Cd2+, Co2+, Ni2+ and Zn2+ were determined according to the Langmuir model, whereby pKD*-values of 3.88 up to 5.02 were revealed. Maximum capacities for the metals were found to be in the range 172 to 1064 mmol/kg.