多种生物质基吸附材料对低浓度稀土离子吸附分离研究
发布时间：2018-10-18 14:56
【摘要】：本文分别以生物质废弃物橘子皮、玉米秸秆和螃蟹壳为原材料,对其进行简单地化学改性,着眼于提高生物质吸附剂的稳定性、吸附容量和分离选择性,开展生物吸附法回收分离溶液中金属离子的应用基础研究,进一步丰富金属离子的生物吸附机理和基础理论研究,简单总结归纳为以下几点：1.以橘子皮为原料,利用橘子皮中大量的果胶分子,经Ca(OH)2皂化使果胶链内或链之间发生交联作用,得到橘子皮吸附剂SOW。该吸附剂对钪、钕、钆、铒的饱和吸附量分别为46.06 mg/g、120.12 mg/g、121.33 mg/g、136.51 mg/g。吸附等温线符合Langmuir吸附模型,吸附动力学符合拟二级动力学方程。利用FTIR和XPS推断SOW吸附稀土金属离子铒的吸附机理为阳离子交换反应。吸附剂表现出明显的凸型的La-Nd; Pm-Gd; Gd-Ho; Er-Lu“四分组效应”。2.以中华绒螯蟹(俗称河蟹)的蟹壳为原料,经过简单处理得到蟹壳壳聚糖。再经过不同氨基酸改性制得一系列壳聚糖吸附剂,分别缩写为Glu-CS, Thr-CS, Lys-CS。经对比,Glu-CS的吸附性能好,这主要是因为三种吸附剂末端氨基酸除了一个羧基之外分别含有一个羧基、羟基和氨基,而与共轭体系相连的取代基羧基相当于吸电子基,羟基和氨基是供电子基,由于p-π共轭效应导致共轭体系的电子云密度增高,酸性降低,rhr-CS和Lys-CS吸附性能较差。此外,研究了Glu-CS对稀土金属离子的吸附能力、最大饱和吸附量以及吸附机理。3.为了进一步提高吸附量,以来源广泛的秸秆为原料,充分利用纤维素上含有的大量羟基功能基团,与1,3-二溴丙烷和亚磷酸三丁酯反应的产物磷酸二丁基溴丙基酯反应制得P-OCS吸附剂,实验还通过3-氯-1,2-丙二醇,增加磷酸基的含量,合成吸附剂P-Gl-OCS。由于P-G1-OCS表面含有双磷酸基团形成分子内氢键导致吸附性能低于P-OCS 。P-OCS对钪、钕、钆、铒的饱和吸附量分别为27.24 mg/g、85.26 mg/g、88 mg/g、76.82 mg/g、P-OCS可从混合稀土金属离子溶液中选择性吸附钪离子,吸附剂稳定性好。通过FTIR、XPS以及pHe的测定,推测吸附机理为磷酸基上的H+与金属离子Er(Ⅲ)的阳离子交换反应。
[Abstract]:In this paper, the biomass-waste orange peel, corn straw and crab shell were used as raw materials, which were chemically modified in order to improve the stability, adsorption capacity and separation selectivity of biomass adsorbents. The basic research on the recovery and separation of metal ions from solution by biosorption is carried out to enrich the biosorption mechanism and basic theory of metal ions, which can be summarized as follows: 1. Using orange peel as raw material, using a large number of pectin molecules in orange peel and saponification of Ca (OH) _ 2, crosslinking occurs in or between pectin chains, the orange peel adsorbent SOW. is obtained. The saturated adsorption capacity of the adsorbent for scandium, neodymium, gadolinium and erbium is 46.06 mg/g,120.12 mg/g,121.33 mg/g,136.51 mg/g., respectively. The adsorption isotherm accords with the Langmuir adsorption model and the adsorption kinetics accords with the pseudo-second-order kinetic equation. The adsorption mechanism of rare earth metal ion erbium adsorbed by SOW was deduced by FTIR and XPS as cationic exchange reaction. The adsorbent showed obvious convex La-Nd; Pm-Gd; Gd-Ho; Er-Lu "four-group effect". 2. The crab shell of Eriocheir sinensis (commonly known as Eriocheir sinensis) was obtained by simple treatment. A series of chitosan adsorbents, abbreviated as Glu-CS, Thr-CS, Lys-CS., were prepared by modifying different amino acids. By contrast, Glu-CS has good adsorption performance, which is mainly due to the fact that the end amino acids of the three adsorbents contain one carboxyl group, one hydroxyl group and one amino group, except for one carboxyl group, while the substituted carboxyl group linked to the conjugated system is equivalent to the electron absorbent group. The electron cloud density of conjugated system increases and the acidity decreases due to p- 蟺 conjugation effect. The adsorption properties of rhr-CS and Lys-CS are poor. In addition, the adsorption capacity, maximum saturated adsorption capacity and adsorption mechanism of Glu-CS for rare earth metal ions were studied. In order to further improve the adsorption capacity, the straw from a wide range of sources as raw materials, the full use of cellulose containing a large number of hydroxyl functional groups, The P-OCS adsorbents were prepared by the reaction of 1-dibromopropane with tributyl phosphite product diDing Ji. The adsorbent P-Gl-OCS was synthesized by increasing the content of phosphoric acid by 3-chloro-1-dibromopropanediol. Due to the formation of intramolecular hydrogen bonds by the presence of diphosphate groups on the surface of P-G1-OCS, the adsorption performance of Scandium, neodymium, gadolinium and erbium on the surface of P-OCS. P-OCS is lower than that of P-OCS. The saturated adsorption capacity of Scandium, neodymium, gadolinium and erbium is 27.24 mg/g,85.26 mg/g,88 mg/g,76.82 mg/g,P-OCS, respectively. The adsorbent has good stability. By the determination of FTIR,XPS and pHe, the adsorption mechanism was deduced to be the cation exchange reaction of H on phosphoric acid with metal ion Er (鈪，
本文编号：2279479
[Abstract]:In this paper, the biomass-waste orange peel, corn straw and crab shell were used as raw materials, which were chemically modified in order to improve the stability, adsorption capacity and separation selectivity of biomass adsorbents. The basic research on the recovery and separation of metal ions from solution by biosorption is carried out to enrich the biosorption mechanism and basic theory of metal ions, which can be summarized as follows: 1. Using orange peel as raw material, using a large number of pectin molecules in orange peel and saponification of Ca (OH) _ 2, crosslinking occurs in or between pectin chains, the orange peel adsorbent SOW. is obtained. The saturated adsorption capacity of the adsorbent for scandium, neodymium, gadolinium and erbium is 46.06 mg/g,120.12 mg/g,121.33 mg/g,136.51 mg/g., respectively. The adsorption isotherm accords with the Langmuir adsorption model and the adsorption kinetics accords with the pseudo-second-order kinetic equation. The adsorption mechanism of rare earth metal ion erbium adsorbed by SOW was deduced by FTIR and XPS as cationic exchange reaction. The adsorbent showed obvious convex La-Nd; Pm-Gd; Gd-Ho; Er-Lu "four-group effect". 2. The crab shell of Eriocheir sinensis (commonly known as Eriocheir sinensis) was obtained by simple treatment. A series of chitosan adsorbents, abbreviated as Glu-CS, Thr-CS, Lys-CS., were prepared by modifying different amino acids. By contrast, Glu-CS has good adsorption performance, which is mainly due to the fact that the end amino acids of the three adsorbents contain one carboxyl group, one hydroxyl group and one amino group, except for one carboxyl group, while the substituted carboxyl group linked to the conjugated system is equivalent to the electron absorbent group. The electron cloud density of conjugated system increases and the acidity decreases due to p- 蟺 conjugation effect. The adsorption properties of rhr-CS and Lys-CS are poor. In addition, the adsorption capacity, maximum saturated adsorption capacity and adsorption mechanism of Glu-CS for rare earth metal ions were studied. In order to further improve the adsorption capacity, the straw from a wide range of sources as raw materials, the full use of cellulose containing a large number of hydroxyl functional groups, The P-OCS adsorbents were prepared by the reaction of 1-dibromopropane with tributyl phosphite product diDing Ji. The adsorbent P-Gl-OCS was synthesized by increasing the content of phosphoric acid by 3-chloro-1-dibromopropanediol. Due to the formation of intramolecular hydrogen bonds by the presence of diphosphate groups on the surface of P-G1-OCS, the adsorption performance of Scandium, neodymium, gadolinium and erbium on the surface of P-OCS. P-OCS is lower than that of P-OCS. The saturated adsorption capacity of Scandium, neodymium, gadolinium and erbium is 27.24 mg/g,85.26 mg/g,88 mg/g,76.82 mg/g,P-OCS, respectively. The adsorbent has good stability. By the determination of FTIR,XPS and pHe, the adsorption mechanism was deduced to be the cation exchange reaction of H on phosphoric acid with metal ion Er (鈪，
本文编号：2279479
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