化學沈澱與樹脂吸附法處理酚衍生物廢水之研究

Phenolic Wastewater Treatment by Chemical Precipitation and Resin Adsorption

黃俊智(Jiun J. Huang)

指導教授 ： 林勝雄

元智大學/工程學院/化學工程與材料科學學系/碩士(2003年)

摘要

酚類化合物普遍存在於許多工業廢水中，而煤礦開採、石油煉製、煉焦工業等為該類化合物之主要來源。目前工業界最常用的處理方法有生物處理、物理或化學吸附、萃取、化學氧化等，雖皆能去除酚類化合物，但卻有處理濃度無法太高、處理成本昂貴等問題，為石化工業帶來很大的困擾。因此，在此研究中針對鄰甲酚、間苯二酚及對氯酚等高濃度酚衍生物廢水以結合化學沈澱與樹脂吸附程序進行處理，探討上述酚衍生物廢水去除之可能性。
化學沈澱法是以批次實驗進行各項變因的探討，實驗結果以水中酚衍生物的去除率為判斷依據。探討的變因包括pH值、溫度、金屬氯化物種類及加藥量。由結果可知，當廢水pH值調至強鹼時，酚衍生物的去除率會有顯著的上升；金屬氯化物的種類，以氯化鋇、氯化鈣、氯化鐵等去除效果較為良好；在實驗中也發現，使用不同沈澱劑時，其所產生之酚酯顆粒粒徑不同，顆粒越大，沈降效果越好，進而會影響其沈降時間快慢。經適當操作條件的選擇，鄰甲酚、間苯二酚、對氯酚去除率分別可達85%、96%及79%左右。
當經由化學沈澱法處理過後，水中酚衍生物濃度不高時，利用XAD-4樹脂吸附法處理，不但較為經濟，並能有效降低水中酚衍生物之濃度，以符合排放標準。在批次等溫吸附實驗中，e-Langmuir能適切的描述其平衡現象，在連續式貫穿吸附實驗中，Simplified Logistic-1、Richards與Hill等方程式皆能適切的模擬貫穿吸附曲線；在樹脂再生部份，由實驗結果得知再生效果良好，並且能有效濃縮酚衍生物濃度，提高回收再利用之可行性。
由以上實驗結果證明，結合化學沈澱法及樹脂吸附法改進了目前高濃度含酚廢水處理方法的缺失，可為現今酚衍生物廢水處理的實際應用提供另一種選擇。

關鍵字

化學沈澱 ； 樹脂吸附 ； 酚衍生物

並列摘要

Abstract
Phenolic compounds are commonly present in various industrial wastewaters. Coal mining, petrochemical refining and coal tar making are typical industries where phenolic compounds exist in the wastewater. Currently, popular methods employed by the industries for treating phenolic wastewater include biological treatment, liquid extraction, adsorption using macroreticular resins and chemical oxidation. Although effective, these methods can only handle phenolic wastewater of limited concentration. Unfortunately, in many cases, the petrochemical wastewater can have phenol concentration exceeding 10,000 mg/l. The treatment method noted above become inadequate . Hence development of chemical or physical methods that is capable of handing high-concentration is necessary. In the present study, we developed a chemical precipitation method in conjunction with adsorption by macroreticular resins for tackling wastewaters containing m-methyl phenol, p-benylphenol or chlorphenol.
Chemical precipitation is to utilize a metal chloride or similar chemicals to react with phenolic compound in the wastewater under alkaline conditions. Due to its low solubility in water, the metal phenolate precipitates out, simultaneously lowering the phenolic concentration in the wastewater. Batch experiments were conducted to explore the effects of pH, amount of metal chloride and temperature on the chemical reaction and phenolate precipitation. Test results indicate that an increase in initial wastewater pH significantly enhances the phenol removal. Ferrous and barium chlorides were found to yield the best overall results in terms of phenol removal and speed of phenolate precipitation. Stoichiometric amount of metal chloride or slightly more than this amount was found sufficient to effect good chemical precipitation.
The phenolic concentration of the wastewater after chemical precipitation was much reduced. Hence adsorption by macroreticular resin was adopted to remove the remaining phenolic compounds. Batch and column experiment tests using XAD-4 were performed to identify the optimum operating conditions. The batch test results show that the extended Langmuir could satisfactorily describes the solid/liquid equilibrium of phenolic compounds. The breakthrough data obtained from column tests reveal that the models of the simplified logistic, Richards or Hill type would be adequate to represent the observed breakthrough data. The phenolic concentration of the wastewater after adsorption was lower than the discharge standard.

並列關鍵字

HASH(0xb20fd74)

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