| In this paper, agricultural and forestry waste rape straw is used as the research object and is modified by tartaric acid and carbon disulfide respectively, two new anionic biological adsorption material is prepared, the scanning electron microscopy (SEM), infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) are used to characterize the morphology and structure before and after the modified adsorbents. Static adsorption behavior of dyes (Methylene Blue and basic magenta) adsorbed by tartaric acid-modified rape straw and unmodified rape straw is investigated, static adsorption behavior of heavy metals (Pb2+ and Cr(VI)) adsorbed by carbon disulfide modified rape straw and unmodified rape straw is investigated, the influence factors of adsorption is also investigated, the mechanism of adsorption and regeneration performance by modified rape straw sorbent is studied. The results are as follows:(1)Preparation and Characterization of tartaric acid modified rape straw adsorbents. In this study, rape straw is modified by tartaric acid to prepare a new anionic tartaric modified adsorbents, modern analytical methods such as SEM, XRD and FT-IR are used to characterize the materials. SEM characterization shows that tartaric acid-modified rape straw (TRS) which has larger specific surface area than natural rape straw(RS) is conducive to adsorption, XRD and FT-IR characterization shows there is no change in crystalline cellulose of modified rape straw and tartaric acid is successfully grafted.(2) Properties and mechanism of dyes adsorption by tartaric acid modified rape straw. Static adsorption behavior of dyes (Methylene Blue and basic magenta) adsorbed by tartaric acid modified rape straw and unmodified rape straw shows that when the pH of Methylene Blue solution is 7, adsorbent dosage is 0.04 mg/g, the pH of basic magenta solution is 5, adsorbent dosage is 0.05mg/g, initial concentration of dyes are 100mg/L, adsorption time is 60min at 20℃, removal of Methylene Blue and basic magenta by modified rape straw works best, the removal rate reached 98.96% and 98.10%; The maximum adsorption capacity of Methylene Blue and basic magenta by tartaric acid modified rape straw is 185.185mg/g and 138.889mg/g. Langmuir isotherm model and the pseudo-second-order kinetic model can simulate the adsorption process of Methylene Blue and basic magenta on modified rape straw, indicating that adsorption process is mainly chemisorption.Methylene Blue adsorption rate maintained at 90.34% and basic magenta maintained at 89.76% after modified rape straw being regenerated by HCl solution for three times,indicating modified adsorbent has a good regeneration performance.(3)Preparation and Characterization of xanthation rape straw adsorbents. In this study, rape straw is modified by carbon disulfide to prepare a new anionic xanthation rape straw adsorbents, modern analytical methods such as SEM, XRD and FT-IR are used to characterize the materials. SEM characterization shows that xanthation rape straw (CRS) which has larger specific surface area than natural rape straw(RS) is conducive to adsorption, XRD characterization shows that carbon disulfide treating changes the crystal form of rape straw cellulose as well as reducing the crystallinity of cellulose. FT-IR characterization shows rape straw cellulose and carbon disulfide successfully undergone xanthation reaction to produce cellulose xanthate.(4) Properties and mechanism of Pb2+ and Cr(Ⅵ) adsorption by xanthation rape straw. Static adsorption behavior of heavy metals (Pb2+ and Cr(Ⅵ)) adsorbed by xanthation rape straw and unmodified rape straw shows that when the pH of Pb2+ solution is 5.5, initial concentration of Pb2+ is 100mg/L, adsorbent dosage is 0.05 mg/g, the pH of Cr(Ⅵ) solution is 5, initial concentration of Cr(Ⅵ) is 50mg/L,adsorbent dosage is 0.1mg/g, adsorption time is 120min at 20℃, removal of Pb2+ and Cr(Ⅵ) by xanthation rape straw works best, the removal rate reached 98.53% and 90.34%; The maximum adsorption capacity of Pb2+ and Cr(Ⅵ) by xanthation rape straw is 62.893mg/g and 15.823mg/g.Langmuir isotherm model and the pseudo-second-order kinetic model can simulate the adsorption process of Pb2+ and Cr(Ⅵ) on xanthation rape straw, indicating that adsorption process is mainly chemisorption.Pb2+ adsorption rate maintained at 82.38% and Cr(Ⅵ) maintained at 57.53% after xanthation rape straw being regenerated by NaOH solution for three times,indicating modified adsorbent has a good regeneration performance.
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