Preparation Of Modified Ulothrix Biosorption Material And Studying Of Its Adsorption Property

In view of the disposal of the low concentration of heavy metal contained in effluent, the modified green algae Ulothrix, which was focused on the high adsorption capcity, was papered by treatment with glutaraldehyde. The microstructure, surface area, chemical structure and adsorptive property of the new biomass were characterized by means of comparing the raw Ulothrix with modified Ulothrix.The results showed the adsorptive capcity of Ulothrix reached hight level when glutaraldehyde percentage was 5%, pH was 1 and modified time was 2 hour, whose special surface improved 56 times comparing with rwa Ulothrix. The results of FTIR analysis showed that modified Ulothrix was loaded the aldehyde functional group and the numberwaves of the hydroxyl and other functional groups were shifted in some degrees. SEM showed that porosity of modified Ulothrix significantly improved.Comparative study on adsorption of Zn(II) ions onto raw Ulothrix and modified showed that the optimal equilibrium conditions changed from pH 6, adsorbent concentration 10 g/L,contact time 3 h, adsorption temperature 25℃ to pH 6.7, concentration of the adsorbent was 4g/L, contact time 2 h, adsorptio n temperature was 25℃. The equilibrium adsorption capacity increased from 0.134 mg/g to 0.563 mg/g and the removal of Zn(II) ions increased from39.5 % to 90.1%. Comparative study on adsorption of Mo(VI) ions onto raw Ulothrix and modified showed showed that the optimal equilibrium conditions changed from pH 1,adsorbent concentration 10 g/L, contact time 3.5 h, adorption temperature was 30℃ to p H 1.5,adsorbent concentration 5 g/L, contact time 3 h, the adsorption temperature was 30℃, their equilibrium adsorption capacity increased from 0.157 mg/g to 0.720 mg/g. The removal of Mo(VI) increased from 37.6% to 92.82%. The adsorptive property and economy of the metals onto Modified Ulothrix had great prespects in development.Thermodynamic resuluts demostrated that adsorption data of Zn(II) ions and Mo(VI)ions onto the modified Ulothrix fitted well with Langmuir adsorption isotherm model, which was illustrated the single molecule layer adsorption.Both of precess of adsorption kinetics fitted well with the pseudo-second-order model,which was illustrated the adsorption process was controlled by molecular diffusion.Thermodynamic parameters of adsotpion of Zn(II) ions onto modified Ulothrix showed thatΔG was-5.45、-6.92 and-8.84 kJ/mol, respectively, ΔH was 80.54 kJ/mol and ΔS was 293.51J/(mol?K) at 293.15 K, 298.15 K and 303.15 K. Thermodynamic parameters of adsotpion of Mo(VI) ions onto modified Ulothrix showed that ΔG was-1.21 、-2.42 and-3.55 kJ/mol,respectively, ΔH was 67.12 kJ/mol and ΔS was 225.77 J/(mol?K) at 303.15 K, 308.15 K and313.15 K. Thermodynamics parameters showed the bioadsoption of Zn(II) ions and Mo(VI)ions onto modified Ulothrix were feasible, spontaneous and endothermic under studiedconditions. Adsorption/desorption results showed that the modified Ulothrix biomass could be used for many times.The results showed that the modified biomass could be used in treatment of heavy metal at low concentration in wastewater and have good prospects in advance.