HUMIC-LIKE COMPOUNDS FORMED FROM L-TRYPTOPHAN AND D-GLUCOSE IN THE PRESENCE OF CU(II)

This study concerns the humic-like polymeric compounds formed by D-glu cose plus L-tryptophan and by L-tryptophan alone, both on Cu-saturated nontronite, montmorillonite and kaolinite and on quartz in the presen ce of Cu(II) ions. These mineral-organic systems were kept in thermost at at 70 degrees C for 30 days and submitted to alternate wetting-dryi ng cycles. Higher amounts of humic-like compounds were extracted from quartz-organic than from clay-organic systems, showing the remarkable action of Cu(II), which even overcame the high catalytic power of clay s. (C) 1997 Elsevier Science Ltd.