Abstract:

Tannin in Casuarina equisetifolia bark was in-situ immobilized by reaction of aldehydes and tannin. The adsorption behavior of the in-situ immobilized modified bark to Cr(Ⅵ) in aqueous solution was investigated. The results showed that the recovery yields of the modified barks were higher than 95% when the mass ratios of the bark to fomaldehyde, glyoxal and glutraldehyde were 1∶20, 1∶4 and 3∶25, respectively. The maximal adsorption capacity of the bark to Cr(Ⅵ) was achieved at pH=2.01. The equilibrium adsorption capacity of the barks modified with fomaldehyde, glyoxal and glutraldehyde was 68.0 mg/g, 83.3 mg/g and 82.0 mg/g, respectively. The pseudosecondorder rate constant decreased with increases in the equilibrium adsorption capacity.

Key words: Casuarina equisetifolia bark, modification, adsorption, Cr (VI)