多種生物質(zhì)基吸附材料對(duì)低濃度稀土離子吸附分離研究
發(fā)布時(shí)間：2018-10-18 14:56
【摘要】：本文分別以生物質(zhì)廢棄物橘子皮、玉米秸稈和螃蟹殼為原材料,對(duì)其進(jìn)行簡(jiǎn)單地化學(xué)改性,著眼于提高生物質(zhì)吸附劑的穩(wěn)定性、吸附容量和分離選擇性,開展生物吸附法回收分離溶液中金屬離子的應(yīng)用基礎(chǔ)研究,進(jìn)一步豐富金屬離子的生物吸附機(jī)理和基礎(chǔ)理論研究,簡(jiǎn)單總結(jié)歸納為以下幾點(diǎn)：1.以橘子皮為原料,利用橘子皮中大量的果膠分子,經(jīng)Ca(OH)2皂化使果膠鏈內(nèi)或鏈之間發(fā)生交聯(lián)作用,得到橘子皮吸附劑SOW。該吸附劑對(duì)鈧、釹、釓、鉺的飽和吸附量分別為46.06 mg/g、120.12 mg/g、121.33 mg/g、136.51 mg/g。吸附等溫線符合Langmuir吸附模型,吸附動(dòng)力學(xué)符合擬二級(jí)動(dòng)力學(xué)方程。利用FTIR和XPS推斷SOW吸附稀土金屬離子鉺的吸附機(jī)理為陽(yáng)離子交換反應(yīng)。吸附劑表現(xiàn)出明顯的凸型的La-Nd; Pm-Gd; Gd-Ho; Er-Lu“四分組效應(yīng)”。2.以中華絨螯蟹(俗稱河蟹)的蟹殼為原料,經(jīng)過(guò)簡(jiǎn)單處理得到蟹殼殼聚糖。再經(jīng)過(guò)不同氨基酸改性制得一系列殼聚糖吸附劑,分別縮寫為Glu-CS, Thr-CS, Lys-CS。經(jīng)對(duì)比,Glu-CS的吸附性能好,這主要是因?yàn)槿N吸附劑末端氨基酸除了一個(gè)羧基之外分別含有一個(gè)羧基、羥基和氨基,而與共軛體系相連的取代基羧基相當(dāng)于吸電子基,羥基和氨基是供電子基,由于p-π共軛效應(yīng)導(dǎo)致共軛體系的電子云密度增高,酸性降低,rhr-CS和Lys-CS吸附性能較差。此外,研究了Glu-CS對(duì)稀土金屬離子的吸附能力、最大飽和吸附量以及吸附機(jī)理。3.為了進(jìn)一步提高吸附量,以來(lái)源廣泛的秸稈為原料,充分利用纖維素上含有的大量羥基功能基團(tuán),與1,3-二溴丙烷和亞磷酸三丁酯反應(yīng)的產(chǎn)物磷酸二丁基溴丙基酯反應(yīng)制得P-OCS吸附劑,實(shí)驗(yàn)還通過(guò)3-氯-1,2-丙二醇,增加磷酸基的含量,合成吸附劑P-Gl-OCS。由于P-G1-OCS表面含有雙磷酸基團(tuán)形成分子內(nèi)氫鍵導(dǎo)致吸附性能低于P-OCS 。P-OCS對(duì)鈧、釹、釓、鉺的飽和吸附量分別為27.24 mg/g、85.26 mg/g、88 mg/g、76.82 mg/g、P-OCS可從混合稀土金屬離子溶液中選擇性吸附鈧離子,吸附劑穩(wěn)定性好。通過(guò)FTIR、XPS以及pHe的測(cè)定,推測(cè)吸附機(jī)理為磷酸基上的H+與金屬離子Er(Ⅲ)的陽(yáng)離子交換反應(yīng)。
[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，
本文編號(hào)：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，
本文編號(hào)：2279479
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