【摘要】：鉻特別是六價鉻Cr(VI)對人體的皮膚、呼吸系統(tǒng)以及消化系統(tǒng)等毒害大,能致癌,是五種劇毒重金屬之一。含鉻廢水是一種對環(huán)境污染最嚴重、對人類危害最大的廢水之一。已研發(fā)的多種含鉻廢水處理方法,由于都存在各種缺點,處理效果難以達到人們期望的目標。因此,開發(fā)新型高效含鉻廢水處理方法具有重要的實際意義。本研究采用螯合沉淀法處理含鉻廢水,在本課題組發(fā)明專利“一種兩性高分子螯合絮凝劑及其制備方法”(ZL200910043653.7)的基礎上,對其進行1m3規(guī)模的放大試驗,成功合成了兩性高分子螯合絮凝劑(PDMAMDTC),并將其應用于鉻鞣廢水和鍍鉻廢水的處理。(1)以二甲基二烯丙基氯化銨、丙烯酰胺、甲醛、三乙烯四胺、二硫化碳和氫氧化鈉為原料,按10L規(guī)模成功合成了兩性高分子重金屬螯合絮凝劑——聚(二甲基二烯丙基氯化銨-丙烯酰胺)基二硫代甲酸鈉(PDMAMDTC)),確定了較佳的工藝流程,完善、優(yōu)化了工藝技術參數:①聚(二甲基二烯丙基氯化銨-丙烯酰胺)(PDMAM)的合成條件:a.單體配比:n(DMDAAC)∶n(AM)=(0.40~0.45)∶1,引發(fā)劑的用量為單體總質量的1.1%~1.2%;b.反應條件:通N2驅氧30 min;反應溫度和時間分別為:第一段為55~60℃,反應時間為2~3 h;第二段反應溫度為65℃,反應時間為0.5 h。②PDMAM-g-TETA的合成條件為:a. n(AM)∶n(HCHO) ∶n(TETA)=1∶0.9~0.95∶1.1~1.2;b.適宜的p H范圍為10.3-10.7;c.反應溫度和時間分別為:第一段為45~50℃,40~50 min;第二段為50~55℃,1.5~2 h。③PDMAMDTC的合成條件:a.PDMAM)-g-TETA的質量百分濃度為4%~5%;b.配比n(TETA)∶n(CS2)∶n(Na OH)=1∶2.5~2.8∶3.25~3.64,c.反應溫度與時間:第一段室溫3~4 h;第二段50~55℃,1.5~2 h。(2)以合成的兩性高分子螯合絮凝劑PDMAMDTC為藥劑,系統(tǒng)研究了其對鉻鞣廢水的處理效果,經實驗室小試和現場1 m3規(guī)模的擴大試驗,確定了鉻鞣廢水處理工藝流程,優(yōu)化、完善了工藝技術參數:①Cr6+還原工序:綠礬加入量:80~82 g/m3;反應時間:30~35 min;溫度:室溫;攪拌速度:40~60 r/min;②螯合反應工序:p H值:7.00~10.00;PDMAMDTC加入量:40~42.5 L/m3鉻鞣廢水;攪拌速度:60~100 r/min;反應時間:15~20 min;③絮凝沉淀工序:0.5‰的PAM加入量:1.5~2 L/m3鉻鞣廢水;攪拌速度:40~60 r/min;攪拌時間:5~10 min;靜置時間:20~30 min。處理后廢水中的總鉻和Cr6+的含量均達到《制革及毛皮加工工業(yè)水污染物排放標準》(GB 30486-2013)的標準,COD達到了《污水綜合排放標準》(GB8978-88)的二級標準。比Na OH、銅試劑、乙二胺多(二硫代甲酸鈉)和市售重金屬捕集劑DTC、重金屬吸附劑RTM比較處理效果好。(3)系統(tǒng)研究了PDMAMDTC對鍍鉻廢水的處理效果,確定了工藝流程和主要工藝參數①以Na HSO3為還原劑能將鍍鉻廢水中的Cr6+有效還原,當Na HSO3的投加量為理論值的1.4倍時,Cr6+基本被還原。Na HSO3的最佳投加量為689.5 mg/L,還原反應時間為10 min,溫度為室溫。②處理鍍鉻廢水的p H值宜控制在6.7~8.5;PDMAMDTC的投加量為7.6~8m L。當鍍鉻廢水CODCr為476 mg/L,總Cr為238.2 mg/L、Cr6+為163.4 mg/L,p H為2.03時,總Cr和COD的去除率分別達到99.60%和94.44%,殘余濁度為1.7 NTU,均低于電鍍污染物排放標準(GB21900-2008);產生的絮體粗大且密實,沉降速度快。綜上所述,以合成的兩性高分子螯合絮凝劑PDMAMDTC處理鉻鞣廢水和鍍鉻廢水等含鉻廢水,處理效果好,工藝簡單,易于操作控制;PDMAMDTC兼具強螯合鉻離子的能力和優(yōu)異的絮凝性能,是一種優(yōu)良的鍍鉻廢水處理劑。本研究為的含鉻廢水的有效治理提供一條切實可行的途徑,具有廣闊的推廣應用價值。
[Abstract]:Chromium, especially hexavalent chromium chromium (VI), is one of the five most toxic heavy metals. Chromium-containing wastewater is one of the most serious environmental pollution and harmful wastewater to human beings. Therefore, it is of great practical significance to develop a new efficient treatment method for chromium-containing wastewater. In this study, the chelating precipitation method was used to treat chromium-containing wastewater. Amphoteric polymeric chelating flocculant (PDMAMDTC) was successfully synthesized and applied to the treatment of chrome tanning wastewater and chrome plating wastewater. (1) Amphoteric polymeric heavy metal chelating flocculation was successfully synthesized on a 10L scale from dimethyldiallylammonium chloride, acrylamide, formaldehyde, triethylenetetramine, carbon disulfide and sodium hydroxide. Poly (dimethyldiallyl ammonium chloride-acrylamide) sodium dithioformate (PDMAMDTC) was used as a n additive to optimize the synthesis conditions of poly (dimethyldiallyl ammonium chloride-acrylamide) (PDMAM):a. The monomer ratio: n (DMDAAC):n (AM)=(0.40~0.45):1, the dosage of initiator. The reaction conditions were as follows: the first stage was 55-60 and the reaction time was 2-3 h; the second stage was 65 and the reaction time was 0.5 H. The synthesis conditions of PDMAM-g-TETA were as follows: a.n (AM):n (HCHO):n (TETA)=1:0.9-0.95:1.1-1.2; and the optimum P H range was 1:0.9-0.95:1.1-1.2. The reaction temperature and time are: the first stage is 45-50 (?) C, 40-50 min; the second stage is 50-55 (?) C, 1.5-2 H. 5~2 H. (2) With the synthetic amphoteric polymer chelating flocculant PDMAMDTC as the reagent, the treatment effect of chrome tanning wastewater was studied systematically. The treatment process of chrome tanning wastewater was determined by laboratory test and 1 m3 scale field test. The process parameters were optimized and improved: 1) Cr6 + reduction process: adding amount of green alum: 80~82 g/m3; Time: 30-35 min; Temperature: Room temperature; Stirring speed: 40-60 r/min; Chelating process: P H: 7.00-10.00; PDMAMDTC: 40-42.5 L/m3 chrome tanning wastewater; Stirring speed: 60-100 r/min; Reaction time: 15-20 min; Flocculation and sedimentation process: 0.5 PAM: 1.5-2 L/m3 chrome tanning wastewater; Stirring speed: 40-60 r/min; Stirring time: 5-10 m chrome tanning wastewater After treatment, the total chromium and chromium ions in the wastewater reached the standard of < discharge standard of water pollutants from tannery and fur processing industry > (GB 30486-2013), and the COD reached the secondary standard of < comprehensive discharge standard of wastewater > (GB8978-88). Compared with Na OH, copper reagent, ethylenediamine (sodium dithiocarbamate) and heavy metal trap on the market. DTC and RTM are better than other heavy metal adsorbents. (3) The treatment effect of PDMAMDTC on chromium plating wastewater is studied systematically, and the technological process and main technological parameters are determined. (1) With Na HSO3 as reducing agent, Cr6+ in chromium plating wastewater can be effectively reduced. When the dosage of Na HSO3 is 1.4 times the theoretical value, Cr6+ is basically reduced. When the dosage is 689.5 mg/L, the reduction reaction time is 10 min, and the temperature is room temperature. NTU, are lower than the electroplating pollutant discharge standard (GB21900-2008); the resulting flocs are coarse and dense, and sedimentation rate is fast. This study provides a feasible way for the effective treatment of chromium-containing wastewater and has broad application value.
【學位授予單位】：湖南科技大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：X703

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