The Treatment Of Highly Concentrated Phenol-containing Wastewater By Membrane Extraction

For recent years, membrane extraction have obtained extensive attention in the field of wastewater treatment, in particular utilized in treating high salty and high concentrated organic wastewater. As homogeneous-phase compact nonporous membrane, silicon rubber membrane selectively permeates a large number of organic molecular and is widely applied in the process of membrane extraction.So this study was focused on high concentrated phenol wastewater treatment performance through two different membrane tubulars, that is, PDMS from abroad and PVMS at home, from Membrane Aromatic Recovery System (MARS). In this study, The factors of influencing disposal efficiency of high concentrated phenol such as: feed velocity, concentration, temperature and pH value of extraction solution and phenol recovery efficiency, besides, optimal operation conditions, service life of experiment equipment and phenol disposal efficiency in practice were investigated. The results showed that: (1) pH value of extraction solution had the greatest effect on disposal efficiency of phenol: the more alkaline, the better disposal efficiency, but to some value, silicon rubber would be corroded severely, service life be shortened;(2) under the optional operation conditions of PDMS membrane tubular: feed flux 2L/d, concentration more than 500mg/L, temperature of extraction solution 50℃,pH value in the range of 12.7-12.8, effluent phenol concentration was less than 500mg/L, phenol disposal efficiency over 96%, recovery rate over 85% and membrane mass transfer coefficient reached to 1.025xl0^-7m/s. When MARS system was put into treating wastewater from Jilin petrochemical benzene-nitrobenzene plant under the above conditions, phenol disposal efficiency was in excess of 95%, service life longer than one year;(3) under the optimal operation conditions of PVMS membrane tubular: feed flux 5L/d, concentration more than 5000mg/L, temperature of extraction solution 50°C, pH value in the range of 12.8-12.9, effluent phenol concentration was less than 300mg/L, phenol disposal efficiency over 97%. It was obviously noted that treatment performance of PVMS excelled over that of PDMS, however, its service life was less than three months.It was indicated that MARS had such distinctive advantages as: high phenol disposal efficiency, high phenol recovery rate, slow membrane fouling, simple installation, easy maintenance, low cost. On the basis of trial results, the pilot project of utilizing PDMS to treat wastewater from Jilin petrochemical benzene-nitrobenzene plant was designed. Under theabove-mentioned optimal operation condition, the project would be taken back the cost in three years.