本文選題：高鉻濃度廢水　切入點(diǎn)：磁粉　出處：《陜西科技大學(xué)》2017年碩士論文

【摘要】：針對(duì)制革中存在的高鉻鉻鞣廢液,本文以磁粉加速氫氧化鉻膠體沉降的加堿磁絮凝技術(shù)進(jìn)行處理,再通過(guò)酸法溶解氫氧化鉻膠體,分離磁粉,并將溶解的氫氧化鉻膠體制成鉻粉,實(shí)現(xiàn)高鉻濃度廢液中的鉻的循環(huán)使用。在加堿磁絮凝處理實(shí)驗(yàn)中,以鉻的去除率和氫氧化鉻沉降速率為指標(biāo),考察了堿用量、時(shí)間、溫度、磁粉用量對(duì)含鉻廢水絮凝的影響,結(jié)果表明:按n(OH-):n(Cr~(3+))=4:1的摩爾比投加氫氧化鈉后,常溫水解30min,鉻離子的水解基本完成,上層清液總鉻含量在30mg/L以下,且當(dāng)磁粉與鉻(以Cr_2O_3計(jì))質(zhì)量比為1:1時(shí),沉降效果最佳。對(duì)于絮凝后所得含磁氫氧化鉻,本論文通過(guò)加濃硫酸溶解氫氧化鉻后再過(guò)濾未溶解磁粉得到含鉻溶液,去除鉻溶液的水分即可得到自制鉻粉。對(duì)自制鉻粉工藝進(jìn)行優(yōu)化后所得鉻粉,在氯化鈉、硫酸鈉、鉻含量、堿度、有機(jī)物含量等指標(biāo)上與工業(yè)鉻粉有所差異。在鞣制時(shí)適當(dāng)增加自制鉻粉的用量,可使其鞣革收縮溫度達(dá)到工業(yè)鉻粉的效果,自制鉻粉鞣革坯顏色較淺,皮身扁薄。針對(duì)中和、復(fù)鞣、染色、加脂等工序產(chǎn)生的廢水含Cr~(3+)較低、及其成分復(fù)雜、難以處理的特點(diǎn),利用已有的從秸稈中通過(guò)微生物發(fā)酵制得的生物絮凝劑對(duì)模擬含鉻溶液中Cr~(3+)進(jìn)行脫除。結(jié)果表明:當(dāng)溫度為30℃,pH為7.5,反應(yīng)總時(shí)間為40min時(shí),生物絮凝劑的脫鉻效果較好,可實(shí)現(xiàn)模擬含鉻溶液中Cr~(3+)濃度低于1.5mg/L的標(biāo)準(zhǔn)。但生物絮凝劑的脫鉻性能受聚丙烯酸復(fù)鞣劑、加脂劑、染料等因素影響,故利用鉻革屑吸附除雜,再用生物絮凝劑處理。對(duì)生物絮凝劑的結(jié)構(gòu)及其脫鉻原理分析如下:(1)生物絮凝劑比表面積較小,吸附能力有限;(2)紅外光譜、紫外光譜、酸堿滴定法表明生物絮凝劑含有較多羧基,約為8mmol/g,使其在堿性水溶液中的溶解性較好,對(duì)陽(yáng)離子性的鉻配合物絮凝作用較強(qiáng);(3)堿性條件下,生物絮凝劑分子鏈上的羧酸類(lèi)基團(tuán)電離度較大,親水性較強(qiáng),鉻配合物的水解、配聚作用較強(qiáng),從而產(chǎn)生吸附、架橋等絮凝作用,有利于鉻的脫除。
[Abstract]:In view of the high chromium chrome tanning waste liquor in tannery, the magnetic powder was treated with alkali magnetic flocculation technology to accelerate the colloidal deposition of chromium hydroxide, and then the chromic hydroxide colloid was dissolved by acid method to separate the magnetic powder. Chromium powder was prepared from the colloidal chromium hydroxide solution to realize the recycling of chromium in the waste liquid with high chromium concentration. In the experiment of adding alkali magnetic flocculation, the removal rate of chromium and the settling rate of chromium hydroxide were used as indexes, and the amount of alkali, time and temperature were investigated. The effect of the amount of magnetic powder on the flocculation of chromium-containing wastewater was studied. The results showed that the hydrolysis of chromium ions was basically completed at room temperature after adding sodium hydroxide at the molar ratio of 4: 1 of n(OH-):n(Cr~(3, and the total chromium content of the supernatant was below 30mg/L. When the mass ratio of magnetic powder to chromium (calculated as Cr_2O_3) is 1:1, the settling effect is the best. For the magnetic chromium hydroxide after flocculation, the chromium-containing solution is obtained by adding concentrated sulfuric acid to dissolve chromium hydroxide and then filtering the insoluble magnetic powder. Self-made chromium powder can be obtained by removing water from chromium solution. After optimizing the process of self-made chromium powder, chromium powder can be obtained in sodium chloride, sodium sulfate, chromium content, alkalinity, etc. The content of organic matter is different from that of industrial chromium powder. The shrinkage temperature of tanning leather can reach the effect of industrial chromium powder when the dosage of self-made chrome powder is increased when tanning, the color of chrome powder tanned by self-made chrome powder is lighter, and the leather is flat and thin. In view of neutralization, the tanning temperature of tanning leather can reach the effect of industrial chromium powder. The wastewater produced by retanning, dyeing and fatliquoring processes contains low Cr~(3), and its components are complex and difficult to deal with. The bioflocculants prepared by microbial fermentation from straw were used to remove Cr~(3 from the simulated chromium-containing solution. The results showed that when the temperature was 30 鈩，

本文編號(hào)：1669184