Removal of terephthalic acid in alkalized wastewater by ferric chloride.
Terephthalic acid, which is a main component in alkali-decrement wastewater, is efficiently removed using ferric chloride in high pH solutions. About 90% removal of terephthalic acid is achieved at pH between 8 and 11. Especially, the removal reached 94.3% at pH 11. However, as the pH increased from pH 12 and 13, the low removal of terephthalic acid were found. The increasing ferric chloride dosage had a dramatic positive impact on the achieved removal of terephthalic acid. Further increase in the ferric chloride dosage did not produce better removal rate. The increase of terephthalic acid concentration also led to the increase of ferric chloride dosage in order to get the same removal of terephthalic acid. There was approximately a negative linear relationship between terephthalic acid concentration and removal of terephthalic acid. Compared with other coagulants, it can be seen that ferric chloride is more effective in a high pH solution and the amount of ferric chloride required is also less as compared with aluminum chloride, magnesium chloride and calcium chloride. Our results clearly showed that terephthalate anions strongly binds to positive Fe(OH)(3) flocs and forms insoluble complexes, probably through a mechanism involving electrostatic attraction. The electrostatic attraction may be particularly useful means of purifying wastewater in high pH solutions.
Wen
Yue-Zhong
YZ
Institute of Environmental Science, Zhejiang University, Hangzhou, Zhejiang 310029, PR China. wenyuezhong@zju.edu.cn
Tong
Shao-Ping
SP
Zheng
Ke-Feng
KF
Wang
Liao-Liao
LL
Lv
Jin-Ze
JZ
Lin
Jun
J
D000327:Adsorption; D000077410:Aluminum Chloride; D017607:Aluminum Compounds / Q000737:chemistry; D002122:Calcium Chloride / Q000737:chemistry; D002712:Chlorides / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D005290:Ferric Compounds / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D007700:Kinetics; D015636:Magnesium Chloride / Q000737:chemistry; D010795:Phthalic Acids / Q000302:isolation & purification*; D055672:Static Electricity; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
D017607:Aluminum Compounds; D002712:Chlorides; D005290:Ferric Compounds; D007220:Industrial Waste; D010795:Phthalic Acids; D014874:Water Pollutants, Chemical; D015636:Magnesium Chloride; D000077410:Aluminum Chloride; C011363:terephthalic acid; D002122:Calcium Chloride; C024555:ferric chloride