Mechanisms of lead biosorption on cellulose/chitin beads.
Environment-friendly cellulose/chitin beads being prepared by coagulating a blend of cellulose and chitin in 6 wt% NaOH/5 wt% thiourea aqueous solution with 5% H2SO4 possessed higher heavy metals uptake capacity than pure chitin flakes. The mechanisms of Pb2+ adsorption on cellulose/chitin beads at pH0=5 were investigated at the molecular levels by scanning electron micrographs (SEM), transmission electron micrographs (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffraction (XRD). The result revealed that mechanisms for the adsorption of Pb2+ on the cellulose/chitin beads could be described as complexation between Pb2+ and N atom in the chitin, and further adsorption of Pb2+ nearby the complexed Pb2+ and precipitation of the hydrolysis product of the Pb2+ complex on the beads as the crystalline state. Furthermore, structural factors such as larger surface area of the beads resulted from microporous-network structure, low crystallinity of cellulose/chitin beads and high hydrophilicity induced by hydrophilic skeleton of cellulose played an important role in increasing adsorption ability.
Zhou
Dao
D
Department of Chemistry, Wuhan University, Wuhan 430072, PR China.
Zhang
Lina
L
Guo
Shenglian
S
D000327:Adsorption; D002482:Cellulose / Q000737:chemistry; D011232:Chemical Precipitation; D002686:Chitin / Q000737:chemistry; D006868:Hydrolysis; D007854:Lead / Q000737:chemistry* / Q000302:isolation & purification; D014873:Water Pollutants / Q000302:isolation & purification; D018508:Water Purification / Q000379:methods*
D014873:Water Pollutants; D002686:Chitin; D007854:Lead; D002482:Cellulose