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  • Investigation on pretreatment of centrifugal mother liquid produced in the production of polyvinyl chloride by air-Fenton technique.

Investigation on pretreatment of centrifugal mother liquid produced in the production of polyvinyl chloride by air-Fenton technique.

Environmental science and pollution research international (2013-03-09)
Yingying Sun, Xiuyi Hua, Rui Ge, Aitong Guo, Zhiyong Guo, Deming Dong, Wentian Sun
ABSTRACT

Centrifugal mother liquid (CML) is one of the main sources of wastewater produced during the production of polyvinyl chloride in chlor-alkali industry. CML is a typical poorly biodegradable organic wastewater, containing many kinds of refractory pollutants. Specifically, it contains dissolved refractory polymers, especially polyvinyl alcohol (PVA), which can pass though the biotreatment processes and clog the membranes used for further treatment. In this study, to ensure the CML applicable to biotreatment and membrane treatment, a novel efficient and mild technique, air-Fenton treatment, was employed as a pretreatment technique to improve biodegradability of the CML and to break down the polymers in the CML. Firstly, the technique was optimized for the CML treatment by optimizing the main parameters, including the dosage of ferrous sulfate, initial pH of the wastewater, [H2O2]/[Fe(2+)], aeration rate, reaction time, and temperature, based on removal efficiency of COD and PVA from the CML. Then, the optimized technique was tested and evaluated. The results indicated that under the optimized conditions, the air-Fenton treatment could remove 66, 98, and 55 % of the COD, PVA, and TOC, respectively, from the CML. After the treatment, biodegradability of the wastewater increased significantly (BOD/COD increased from 0.31 to 0.68), and almost all of the PVA polymers were removed or broken down. Meanwhile, concentration of the remaining iron ions, which were added during the treatment, was also quite low (only 2.9 mg/L). Furthermore, most of the suspended materials and ammonia nitrogen, and some of the phosphorus in the wastewater were removed simultaneously.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Mowiol® 10-98, Mw ~61,000
Sigma-Aldrich
Mowiol® 6-98, Mw ~47,000
Sigma-Aldrich
Poly(vinyl alcohol), average Mw 130,000, 99+% hydrolyzed
Sigma-Aldrich
Mowiol® 4-98, Mw ~27,000
Sigma-Aldrich
Mowiol® 8-88, Mw ~67,000
Sigma-Aldrich
Poly(vinyl alcohol), Mw 89,000-98,000, 99+% hydrolyzed
Sigma-Aldrich
Poly(vinyl alcohol), Mw 31,000-50,000, 98-99% hydrolyzed
Sigma-Aldrich
Poly(vinyl alcohol), average Mw 146,000-186,000, 87-89% hydrolyzed
Sigma-Aldrich
Poly(vinyl alcohol), Mw 13,000-23,000, 87-89% hydrolyzed
Sigma-Aldrich
Poly(vinyl alcohol), average Mw 85,000-124,000, 87-89% hydrolyzed
Sigma-Aldrich
Poly(vinyl alcohol), Mw 85,000-124,000, 99+% hydrolyzed
Sigma-Aldrich
Poly(vinyl alcohol), average Mw 31,000-50,000, 87-89% hydrolyzed
Sigma-Aldrich
Poly(vinyl alcohol), Mw 9,000-10,000, 80% hydrolyzed
Sigma-Aldrich
Poly(vinyl alcohol), average Mw 13,000-23,000, 98% hydrolyzed
Sigma-Aldrich
Mowiol® 20-98, Mw ~125,000
Sigma-Aldrich
Poly(vinyl alcohol), Fully hydrolyzed
Sigma-Aldrich
Mowiol® 4-88, Mw ~31,000
Sigma-Aldrich
Poly(vinyl alcohol), 87-90% hydrolyzed, average mol wt 30,000-70,000
Sigma-Aldrich
Poly(vinyl alcohol), Mw 146,000-186,000, 99+% hydrolyzed
Sigma-Aldrich
Mowiol® 18-88, Mw ~130,000
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Mowiol® 56-98, Mw ~195,000
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Poly(vinyl chloride), average Mw ~233,000, average Mn ~99,000
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Poly(vinyl chloride), average Mw ~43,000, average Mn ~22,000
Supelco
Poly(vinyl chloride), Selectophore, high molecular weight
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Poly(vinyl chloride), high molecular weight
Sigma-Aldrich
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Supelco
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Sigma-Aldrich
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Sigma-Aldrich
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