| With the rural economic developed and the standard of people living improved, the agricultural by-products increased year by year. Corn stalks (CS) as one of the three major agricultural wastes in China, its production of waste amount was the particularly alarming. From the fundamental solution to the comprehensive use of CS has been extremely urgent. Therefore, exploring the effective way of the industrialization of agricultural by-products has the very vital significance.Pollution by heavy metals ion considered as a major pollutant in ecological environment pollution has caused directly or indirectly great hazards to the human health. And there has been a great increase and accumulation in environment due to the rapid industrialization over the years. Sources of heavy metal ions waste include electroplating, metallurgy, leather tanning and textile dyeing industries, resulting in a large quantity of heavy metal ions being discharged into effluent industrial wastewaters. Therefore, choose a reasonable method for effective treatment of heavy-metal-containing wastewater has great significance to control the metal ions pollution and guarantee human health. The widely adopted method in removal of heavy metal ions from wastewaters was adsorption, due to its equipment simple, comprehensive application, effective treatment and sustainable use of regeneration absorbent. The most generally used adsorbent is activated carbon. Although activated carbon is effective in removal of heavy metal ions from wastewaters, it is expensive cost and difficult regeneration limited its use. For this reason, many scholars were looking at the wide-source and low-cost agricultural wastes to prepare efficient cellulosic-based adsorbent, to treatment with heavy metal ions pollution wastewaters. In order to achieve waste treat waste, realizing the social, economic and environmental benefits unity. Therefore, how to effectively use the agricultural wastes to solve the problem of heavy metal ions in the water will become the research focus.For the above question, this paper through modification of CS fiber cellulose structure, open the key link of the cellulose molecules chain and graft new functional group, to change the fiber intrinsic character and prepare the higher capacity absorbent. Then applied the modified corn stalk (MCS) to study the adsorption of the simulate Cr(VI) waste water. The MCS was tested for its ability to remove Cr(VI) from aqueous solution by batch static adsorption and dynamic column adsorption, and the mechanism of the adsorption process was determined.1. A new adsorbent modified from CS was synthesized after cross-linking with diethylenetriamine (DETA) and graft copolymerization with triethylamine. Modification results showed that the Cr(VI) anion-adsorbing capacity of MCS has been greatly improved than that of raw CS. The performance of the MCS characterized by element analysis, SEM, BET and TG analysis founded that the N element content increased, thermal stability improved, fiber surface became smooth and orderly, specific surface area reduced of MCS. The results of FTIR and Raman spectrum analysis founded that the group structure of MCS surface has been changed and successfully introduced a large number of amino groups. And the mechanism of adsorption Cr (VI) was mainly ion exchange.2. The effect of different cross-linking agents on the modification of CS showed that cross-linking agent in the modification of CS process plays a very important role, the greater cross-linking degree, the bigger adsorption ability of MCS. But using DETA as cross-linking agent modified CS has better thermal stability.3. Batch static adsorption results showed that the removal efficiency of Cr(VI) ions increased significantly with the dosage of MCS. When the adsorption concentration was1.5g/L, MCS has the best removal on Cr(VI) of99.8%, which was higher than that of CS (34.5%). The adsorption process of Cr (VI) onto modified corn straw is very fast. The initial pH value of solution is an important controlling parameter in the Cr (VI) adsorption process, due to its affect on the Cr(VI) ionic state and the charge of the functional group on the adsorbent surface. The batch equilibrium data fitted well to the Langmuir and Freundlich isotherms. Maximum adsorption capacity of MCS for Cr(VI) was200.00mg/g at303K which was relatively large compared to some adsorbents as reported. Kinetic data were best fitted with the pseudo-second-order kinetic model. The adsorption process was controlled by the intra-particle diffusion and membrane diffusion process. The thermodynamic parameters showed that the adsorption of Cr(VI) onto MCS was an spontaneous and endothermic process. As the temperature rise, the adsorption process proceeded faster.4. Continuous fixed-bed column studies showed that the exhaustion time decreased with decrease of bed depth, increase of flow rate and influent concentration. Consistent with batch static adsorption experiment, MCS states the excellent adsorption capacity for the removal of low Cr(VI) concentration. The Thomas and Yoon-Nelson models were good applied to the adsorption of Cr(VI). The predicted breakthrough curves and evaluated the model parameters of the fixed-bed column are useful for process design. MCS dynamic column has stable performance of adsorption Cr(VI), and compared to other absorbents reported in the literature, MCS exhibits high adsorption ability of Cr(VI) ion.These results showed that MCS could be considered as a potential and effective adsorbent for the removal of Cr(VI) ions from aqueous solution.
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