Question

. A particular lake sediment sample is made up of 23% organic matter and 77% mineral fraction, the latter containing: 42% clay minerals; 24% silt, 11 % sand. The clay minerals are 90% kaolinite and 10% halloysite. Calculate an approximate cation-exchange capacity (cmol(+) kg^-1).

Answers: CEC_kaolinite = 3.0 cmol (+)/kg, CEC_halloysite = 0.34 cmol (+)/kg

CEC_OM = 46 cmol (+)/kg Total CEC = 49 cmol (+)/kg