The Preparation Of Superfine Down Particle And Its Absorption Behavior On Dyes

Accompany with continuous and rapid development of Chinese economy, rapid growthof the population and rapid expansion of the city, the environmental pollution problemsbecomes more and more serious, especially in water pollution. Dye wastewater is one of themost difficult treatment industrial wastewater for its high organic content, deep chromaticityand complex component.Down fiber, a natural protein fiber, has long been used as high quality textile materialsfor its moderate moisture absorption and retention property. Poultry farms in China producedabout0.2billion kg of down fiber every year. However, a large amount of down fiber is oftenprocessed into a low quality protein supplement for animal feed after usage or disposed aswastes, which not only a huge waste of energy resources, but also bring high pressure to theenvironment protection.Aiming at the resource utilization of down fiber, solving the increasingly seriousproblem of dye wastewater treatment, the paper uses superfine down particle (SDP) as alow-cost adsorbent for the removal of acid brilliant scarlet3R, direct fast scarlet4BS and vatscarlet R from aqueous solution. The particle size analyzer, N2adsorption/desorption, XRD,Scanning Electron Microscopy (SEM), elementary analyzer and Fourier Transform InfraredSpectroscopy (FTIR) were used to characterize the adsorbent material, respectively. Toidentify the optimum adsorption conditions and explore the mechanism of adsorption, theadsorption potential of SDP has been studied by batch adsorption technique. It is showed thatthe surface of SDP is very rough and showed many pores. The particle size was mainlybetween0.2μm and12μm, and the average size of superfine down particle was around2.34±0.26μm by calculating. N2adsorption/desorption experiment also showed that thesurface area of SDP was7277cm2/g and the average pore size was9.88nm, which suggestedthat SDP was mesoporous adsorbent. XRD results also showed that the degree of crystallinityof SDP was43.26%, which indicated that SDP was a β-sheet structure protein and it hadaggregation structure of coexistence state of crystalline region and amorphous area. The experiments studied the adsorption process of acid brilliant scarlet3R, direct fastscarlet4BS and vat scarlet R onto SDP under different conditions. The fitted resulted ofLangmuir adsorption model showed that the adsorption behavior of acid brilliant scarlet3Ronto SDP was the best in the three dyes and the maximum adsorption capacity was found tobe137.5516mg/g at their optimum conditions. Based on the above studies, the adsorptionthermodynamics and kinetics of acid brilliant scarlet3R onto SDP at the differenttemperatures were also studied. The optimum dye removal could be obtained at pH2.0,adsorbent dose5g/L, initial dye concentration800mg/L and adsorption time less than3h fromthe perspective of application of economy. According to Arrhenius equation, the activationenergy (Ea) of dye adsorption was determined as59.516kJ/mol, which indicated theadsorption process was chemisorption. Thermodynamic parameters such as Gibbs free energy(ΔG0), enthalpy (ΔH0), and entropy (ΔS0) were also calculated and it was found that theadsorption of dye onto SDP was spontaneous and endothermic in nature and highertemperature is beneficial to the adsorption. The results of kinetics studies showed that theadsorption followed the pseudo-second-order kinetics model, which indicated that theadsorption involved chemical reactions in addition to physic adsorption. It is conclusions thatthe mechanism of acid brilliant scarlet3R onto SDP was rather complex, which is not onlyionic bonding force between dye and adsorbent molecules causing orientation adsorption ofdye molecules on SDP, but also hydrogen bond and Van der Walls force.In all, superfine down particle had potential application as adsorbent for removal of acidbrilliant scarlet3R, direct fast scarlet4BS and vat scarlet R from aqueous solution. It hadprovided a research basis and theoretical support for the subsequent experiment using SDP totreat dyeing wastewater and other refractory organic water.