摘要重金属离子污染一直以来都是水体污染中较为严重的部分，处理低浓度重金属离子的传统方法如氧化还原法、生物法等存在成本高或者难于回收的问题。生物质材料来源广泛、价格低廉、选择性优良、重金属离子去除率高。本论文考察了生物质材料吸附剂（核桃壳粉、柚子皮粉、小麦秸秆粉）投加量、初始Cr(Ⅵ)浓度、初始pH值、吸附时间、吸附温度，对水样中Cr(Ⅵ)的吸附效果。分析生物质材料对冶金废水中Cr(Ⅵ)吸附的热力学、动力学行为。87191

实验结果表明:随着吸附条件的变化，三种吸附剂对废水中Cr(Ⅵ)的吸附效果均呈现出相似的变化趋势。随着吸附剂投加量的增加、吸附时间延长、吸附温度的提高，三种吸附剂对Cr(Ⅵ)吸附率都逐渐上升。在吸附剂投加量为1 g、吸附时间120 min、吸附温度为20℃时，改性20目核桃壳粉的吸附效果较佳，吸附率达到88。7%；吸附剂投加量为0。2 g、吸附时间90 min、温度20℃时，改性60目柚子皮粉的吸附率达到81。4%；改性40目小麦秸秆粉吸附剂的投加量为0。5 g、吸附时间为120 min、吸附温度为20℃时，吸附率达到90。6%。随着废水初始含Cr(Ⅵ)浓度与废水初始pH的增大，单位质量吸附剂对Cr(Ⅵ)的吸附率均有所下降。在控制单一变量的情况下，Cr(Ⅵ)浓度为10 mg/L时，核桃壳粉与小麦秸秆粉的吸附率最高，分别为91。8%、92%。柚子皮粉的吸附率在Cr(Ⅵ)浓度为20 mg/L时最高，为81。4%；废水初始pH为1时，三种吸附剂（核桃壳粉、柚子皮粉、小麦秸秆粉）吸附率均达到最高分别为90%、82。3%、92。4%。准二级动力学模型更适合用来描述三种生物质材料吸附Cr(Ⅵ)的动力学行为，表明化学吸附机理在吸附Cr(Ⅵ)的过程中起着主导作用；W-M动力学模型的拟合结果表明内扩散和液膜扩散为吸附Cr(Ⅵ)速率控制步骤。热力学模型分析，核桃壳粉与柚子皮粉对Cr(Ⅵ)的吸附过程符合Langmuir等温吸附模型；对于小麦秸秆粉吸附行为，Langmuir和Freundlich等温吸附模型都较好地反映小麦秸秆粉对溶液中Cr(Ⅵ)的吸附行为，但相比而言Langmuir等温吸附模型更加符合其吸附过程。

毕业论文关键词：生物质材料；吸附；Cr(Ⅵ)

Abstract Heavy metal ion contamination has always been more serious water pollution in part, the traditional approach to low concentrations of heavy metal ions such as high oxidation-reduction method, biological method or the presence of cost recovery and other difficult issues。 Wide variety of sources of biomass materials, low prices, excellent selectivity, high heavy metal ion removal。 This paper examines the biomass adsorbent material (walnut shell powder, orange peel powder, wheat straw powder) the dosage, initial Cr(Ⅵ) concentration, initial pH value, adsorption time and temperature of the water samples Cr(Ⅵ) adsorption effect。 Thermodynamic analysis of biomass materials for metallurgical wastewater by Cr(Ⅵ) adsorption kinetics behavior。

The results show that with the change of the adsorption conditions, the adsorption effect of three types of absorbents in wastewater Cr(Ⅵ) both showed similar trends。 With the increase of adsorbent dosage, prolonged adsorption, adsorption temperature increases three adsorbent Cr(Ⅵ) adsorption rate is gradually increased。 Adsorbent dosage of 1 g, adsorption time 120 min, the adsorption temperature is 20℃, the adsorption effect of walnut shell powder 20 mesh modified preferred adsorption rate reached 88。7%; adsorbent dosage 0。2 g, adsorption time 90 min, temperature 20℃, the adsorption rate of 60 mesh modified orange peel powder reached 81。4%; 40 mesh dosage modified wheat straw powder adsorbent is 0。5 g, adsorption time is 120 min, the adsorption temperature is 20 ℃, adsorption rate of 90。6%。 With the initial wastewater containing Cr(Ⅵ) concentration and initial pH increases, the decline in unit mass of adsorbent for Cr(Ⅵ) adsorption rate。 In the case of control of a single variable, Cr(Ⅵ) concentration of 10mg / L, the adsorption rate of walnut shell powder and wheat straw powder of the highest, 91。8%, 92%。 Pink grapefruit skin absorption rate in Cr(Ⅵ) concentration of 20 mg/L when the highest 81。4%; initial pH is 1, three types of absorbents (walnut shell powder, orange peel powder, wheat straw powder) adsorption rate the highest 90%, respectively, 82。3%, 92。4%。 Quasi-second-order kinetic model is more suitable to describe three biomass material adsorbed Cr(Ⅵ) dynamic behavior, indicating chemical adsorption mechanism plays a leading role in the process of adsorption of Cr(Ⅵ) in; quasi W-M Dynamic Model the results showed that combined internal diffusion film diffusion and adsorption Cr(Ⅵ) rate controlling step。 Thermodynamic model, walnut shell powder and orange peel powder to Cr(Ⅵ) adsorption process the Langmuir isotherm model; the adsorption behavior of wheat straw powder, Langmuir and Freundlich isotherm models better reflect the wheat straw powder for solution Cr(Ⅵ) adsorption behavior, there is far Langmuir isotherm model more in line with the adsorption process。