螯合—絮凝劑二硫代羧基化殼聚糖的制備及其捕集重金屬性能研究
發(fā)布時間：2019-03-06 14:52
【摘要】：作為自然界的堿性天然高分子多糖,殼聚糖分子結構中含有大量的氨基、羥基和N-乙�；钚怨δ軋F,特別是氨基N原子上的孤對電子可進入到重金屬離子的空軌道上,通過配位鍵結合,形成穩(wěn)定的螯合物,可去除許多種金屬離子。對殼聚糖進行化學改性并將其應用于水處理領域已成為近年來研究的熱點。論文以殼聚糖為母體,采用化學合成方法將含硫原子配位基團即二硫代羧基引入其分子結構中,制備出對重金屬具有螯合和絮凝雙重作用的新型高分子絮凝劑二硫代羧基化殼聚糖(DTCTS)。本文以殼聚糖(CTS)、二硫化碳(CS2)、氫氧化鈉(NaOH)為原料,采用單因素實驗法、正交實驗法以及響應面法確定了DTCTS的最佳制備條件,并通過使用電鏡掃描、紫外光譜分析、紅外分析及元素分析等方法對DTCTS進行了表征。同時通過絮凝沉淀實驗研究了DTCTS對重金屬的捕集及除濁性能;并對DTCTS的溶液特性及存放穩(wěn)定性,重金屬螯合絮體的分形維數(shù)和絮體的穩(wěn)定性及重金屬回收性能進行了探討。實驗結果如下:(1)通過單因素實驗確定影響DTCTS合成的主要因素有:反應物CTS、NaOH、CS2的摩爾比例、殼聚糖分子量和脫乙酰度、殼聚糖濃度、預反應時間及主反應時間、預反應溫度及主反應溫度等。(2)選擇反應物摩爾比例、預反應溫度及主反應溫度、預反應時間及主反應時間進行正交實驗,并分別以水樣中Cu2+、Cd2+(投藥量300mg/L和360mg/L)去除率為考察指標,得到四組不同的最優(yōu)合成條件。表明正交實驗的優(yōu)化組合條件受離子種類和DTCTS投加量的影響。(3)選取正交實驗對DTCTS合成影響最大的三個主要因素:反應物摩爾比例、預反應時間t1、主反應溫度T2進行響應面實驗,得出DTCTS的最佳制備條件為:反應物CTS、CS2、NaOH三者的摩爾比例為1:1.5:2,預反應溫度T1為25℃,預反應時間t1為30min,主反應溫度T2為60℃,主反應時間t2為120min。該優(yōu)化組合條件不受離子種類的影響,具有通用性。避免針對不同重金屬離子而制備不同的DTCTS,由此簡化了合成過程。(4)DTCTS屬于兩性高分子絮凝劑,其在蒸餾水體系中的等電點pHiep為6.8,在自來水體系中的等電點pHiep為6.0。(5)DTCTS對含單一重金屬(Cu2+、Cd2+、Pb2+)廢水有很好的去除效果,且所需pH值較低。當pH值為6.0,在最佳投藥量下,DTCTS對Cu2+、Cd2+、Pb2+的去除率均可達100%;對于含Ni2+廢水DTCTS處理效果不佳,在DTCTS投加量為720mg/L時,去除率僅為86.18%,需進一步增大投藥量才能達到較好的去除效果。DTCTS對于混合重金屬離子的總體捕集順序為Cu2+Pb2+Cd2+Ni2+。(6)EDTA、濁度對DTCTS捕集重金屬離子的影響不同。EDTA對DTCTS除Cu2+和Cd2+均有明顯的抑制作用,但通過增大DTCTS投加量可以使抑制作用減弱;濁度對DTCTS除Cu2+、Cd2+的促進或抑制作用不明顯,但是當重金屬離子存在時,DTCTS除濁效果明顯增加。(7)DTCTS與重金屬形成的螯合絮體分形維數(shù)越大,重金屬的去除率越高;DTCTS螯合絮體穩(wěn)定性和回收性能較好,這有利于DTCTS的實際應用。本文制備的新型高分子螯合絮凝劑DTCTS對重金屬離子具有良好的捕集效果,在適宜的條件下可有效去除多種重金屬離子,且絮體沉降性好,使重金屬廢水處理簡單易行,對含重金屬廢水處理具有廣闊的應用前景。
[Abstract]:As the basic natural high molecular polysaccharide of the natural world, the molecular structure of the chitosan contains a large amount of amino, hydroxyl and N-ethanediyl active functional groups, in particular, the lone pair of electrons on the amino N atom can enter an empty track of heavy metal ions, and the chitosan molecular structure can be combined by a coordination bond, A stable laminate can be formed to remove a wide variety of metal ions. The chemical modification of chitosan and its application in the field of water treatment have become the hot spot in recent years. In this paper, a novel high-molecular flocculant-based chitosan (DTCTS), which is a new kind of high-molecular flocculant, is prepared by introducing a sulfur-containing atom coordination group or a dithiocarbamate group into the molecular structure by adopting a chemical synthesis method as a mother material and adopting a chemical synthesis method. The best preparation conditions of DTCTS were determined by single factor experimental method, orthogonal experiment method and response surface method with chitosan (CTS), carbon disulfide (CS2) and sodium hydroxide (NaOH), and by using electron microscope scanning and ultraviolet spectrum analysis, The DTCTS was characterized by IR analysis and elemental analysis. The effects of DCTS on the collection and turbidity removal of heavy metals were studied by means of flocculation and precipitation, and the solution properties and storage stability of DTCTS, the fractal dimension of heavy metals and the floc and the stability of the floc and the recovery of heavy metals were discussed. The results of the experiment were as follows: (1) The main factors affecting the synthesis of DCTS were determined by single factor experiment: the molar ratio of CTS, NaOH, CS2, the molecular weight of chitosan, the deacetylation degree, the concentration of chitosan, the pre-reaction time, the main reaction time, the pre-reaction temperature and the main reaction temperature. (2) The molar ratio of the reactants, the pre-reaction temperature and the main reaction temperature, the pre-reaction time and the main reaction time were selected for the orthogonal experiment, and the removal rate of Cu2 +, Cd2 + (the dosage of 300 mg/ L and 360 mg/ L) in the water sample was taken as the study index, and four groups of different optimal synthesis conditions were obtained. It is shown that the optimal combination condition of the orthogonal experiment is influenced by the ionic species and the dosage of the DTCTS. and (3) selecting three main factors which have the greatest influence on the synthesis of the DTCTS by the orthogonal experiment: the molar ratio of the reactants, the pre-reaction time t1 and the main reaction temperature T2 are subjected to response surface experiments, and the optimal preparation conditions of the DCTS are as follows: the molar ratio of the reactants CTS, CS2 and NaOH is 1: 1.5:2, The pre-reaction temperature T1 is 25 DEG C, the pre-reaction time t1 is 30 min, the main reaction temperature T2 is 60 DEG C, and the main reaction time t2 is 120 min. The optimized combination condition is not influenced by the ion species, and has the universality. Different DTCTS can be prepared for different heavy metal ions, thereby simplifying the synthesis process. (4) DTCTS is a amphoteric polymeric flocculant, which has a pH of 6.8 in the distilled water system and 6.0 in the tap water system. (5) DCTS has good removal effect on wastewater containing single heavy metal (Cu2 +, Cd2 +, Pb2 +), and the required pH value is low. When the pH value is 6.0, the removal rate of the DTCTS to Cu2 +, Cd2 + and Pb2 + can be up to 100% under the optimal dosage, and the removal rate is only 86.18% for the DCTS containing Ni2 + wastewater and the dosage of DTCTS is 720 mg/ L. The total trapping order of DTCTS for mixed heavy metal ions is Cu2 + Pb2 + Cd2 + Ni2 +. (6) The influence of EDTA and turbidity on heavy metal ions trapped by DTCTS was different. EDTA has a significant inhibitory effect on DCTS except for Cu2 + and Cd2 +, but by increasing the dosage of DCTS, the inhibition of DCTS is not obvious, but the effect of turbidity on the removal of Cu2 + and Cd2 + in DCTS is not obvious, but when heavy metal ions are present, the effect of DCTS is obviously increased. (7) The larger the fractal dimension of DCTS and heavy metals, the higher the removal rate of heavy metals, and the better stability and recovery performance of DTCTS, which is beneficial to the practical application of DTCTS. The novel high-molecular compound flocculant DTCTS prepared by the invention has good trapping effect on heavy metal ions, can effectively remove various heavy metal ions under suitable conditions, and has good floc sedimentation property, so that the waste water treatment of the heavy metal is simple and feasible, And has wide application prospect to the wastewater containing heavy metal.
【學位授予單位】：蘭州交通大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TQ317;X703
本文編號：2435625
[Abstract]:As the basic natural high molecular polysaccharide of the natural world, the molecular structure of the chitosan contains a large amount of amino, hydroxyl and N-ethanediyl active functional groups, in particular, the lone pair of electrons on the amino N atom can enter an empty track of heavy metal ions, and the chitosan molecular structure can be combined by a coordination bond, A stable laminate can be formed to remove a wide variety of metal ions. The chemical modification of chitosan and its application in the field of water treatment have become the hot spot in recent years. In this paper, a novel high-molecular flocculant-based chitosan (DTCTS), which is a new kind of high-molecular flocculant, is prepared by introducing a sulfur-containing atom coordination group or a dithiocarbamate group into the molecular structure by adopting a chemical synthesis method as a mother material and adopting a chemical synthesis method. The best preparation conditions of DTCTS were determined by single factor experimental method, orthogonal experiment method and response surface method with chitosan (CTS), carbon disulfide (CS2) and sodium hydroxide (NaOH), and by using electron microscope scanning and ultraviolet spectrum analysis, The DTCTS was characterized by IR analysis and elemental analysis. The effects of DCTS on the collection and turbidity removal of heavy metals were studied by means of flocculation and precipitation, and the solution properties and storage stability of DTCTS, the fractal dimension of heavy metals and the floc and the stability of the floc and the recovery of heavy metals were discussed. The results of the experiment were as follows: (1) The main factors affecting the synthesis of DCTS were determined by single factor experiment: the molar ratio of CTS, NaOH, CS2, the molecular weight of chitosan, the deacetylation degree, the concentration of chitosan, the pre-reaction time, the main reaction time, the pre-reaction temperature and the main reaction temperature. (2) The molar ratio of the reactants, the pre-reaction temperature and the main reaction temperature, the pre-reaction time and the main reaction time were selected for the orthogonal experiment, and the removal rate of Cu2 +, Cd2 + (the dosage of 300 mg/ L and 360 mg/ L) in the water sample was taken as the study index, and four groups of different optimal synthesis conditions were obtained. It is shown that the optimal combination condition of the orthogonal experiment is influenced by the ionic species and the dosage of the DTCTS. and (3) selecting three main factors which have the greatest influence on the synthesis of the DTCTS by the orthogonal experiment: the molar ratio of the reactants, the pre-reaction time t1 and the main reaction temperature T2 are subjected to response surface experiments, and the optimal preparation conditions of the DCTS are as follows: the molar ratio of the reactants CTS, CS2 and NaOH is 1: 1.5:2, The pre-reaction temperature T1 is 25 DEG C, the pre-reaction time t1 is 30 min, the main reaction temperature T2 is 60 DEG C, and the main reaction time t2 is 120 min. The optimized combination condition is not influenced by the ion species, and has the universality. Different DTCTS can be prepared for different heavy metal ions, thereby simplifying the synthesis process. (4) DTCTS is a amphoteric polymeric flocculant, which has a pH of 6.8 in the distilled water system and 6.0 in the tap water system. (5) DCTS has good removal effect on wastewater containing single heavy metal (Cu2 +, Cd2 +, Pb2 +), and the required pH value is low. When the pH value is 6.0, the removal rate of the DTCTS to Cu2 +, Cd2 + and Pb2 + can be up to 100% under the optimal dosage, and the removal rate is only 86.18% for the DCTS containing Ni2 + wastewater and the dosage of DTCTS is 720 mg/ L. The total trapping order of DTCTS for mixed heavy metal ions is Cu2 + Pb2 + Cd2 + Ni2 +. (6) The influence of EDTA and turbidity on heavy metal ions trapped by DTCTS was different. EDTA has a significant inhibitory effect on DCTS except for Cu2 + and Cd2 +, but by increasing the dosage of DCTS, the inhibition of DCTS is not obvious, but the effect of turbidity on the removal of Cu2 + and Cd2 + in DCTS is not obvious, but when heavy metal ions are present, the effect of DCTS is obviously increased. (7) The larger the fractal dimension of DCTS and heavy metals, the higher the removal rate of heavy metals, and the better stability and recovery performance of DTCTS, which is beneficial to the practical application of DTCTS. The novel high-molecular compound flocculant DTCTS prepared by the invention has good trapping effect on heavy metal ions, can effectively remove various heavy metal ions under suitable conditions, and has good floc sedimentation property, so that the waste water treatment of the heavy metal is simple and feasible, And has wide application prospect to the wastewater containing heavy metal.
【學位授予單位】：蘭州交通大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TQ317;X703
【參考文獻】
相關期刊論文 前3條
1 蔡照勝,楊春生,王錦堂,許琦,嚴金龍;季銨化殼聚糖及其絮凝六價鉻性能的研究[J];工業(yè)用水與廢水;2005年02期
2 張同勝;含重金屬離子廢水處理過程中pH值的設定[J];硫酸工業(yè);2005年04期
3 劉長嵐,崔文新,李成彬;殼聚糖及其衍生物在化工方面應用的研究[J];山東師范大學學報(自然科學版);2003年03期
，本文編號：2435625
本文鏈接：http://sikaile.net/kejilunwen/huanjinggongchenglunwen/2435625.html
最近更新
教材專著
