Flocculation studies between dual polymers on pulp and paper mill wastewater are reported in this paper. The effects of different molecular weights of polyDADMAC and different dosages of Polyacrylamide (PAM) were stud...Flocculation studies between dual polymers on pulp and paper mill wastewater are reported in this paper. The effects of different molecular weights of polyDADMAC and different dosages of Polyacrylamide (PAM) were studied. The molecular weights of polyDADMAC used were 8.8×104, 10.5×104 and 15.7×104 g/mol. The flocculation performance was analyzed in jar tests with PolyDADMAC and Polyacrylamide dosages ranging from 0.4-2.0 mg/L﹣1 and 0.4-8.0 mg/L﹣1 respectively. A higher molecular weight and a 6.0 mg/L﹣1 dosagepolyDADMAC gave the highest level of flocculation based on turbidity and TSS removal. In addition, increasing the molecular weight of PolyDADMAC increased ζ potential values approaching zero. This indicated that polyDADMAC acts as a destabilizer. Based on TSS, the addition of PAM will improve the size of microflocs created by polyDADMAC. It demonstrates that PAM acts as a bridger between microflocs.展开更多
In water treatment processes and conditioning drinking water, PEs are widely used;however, their environmental impact is still doubtful, since residual concentrations increase organic matter content and represents a p...In water treatment processes and conditioning drinking water, PEs are widely used;however, their environmental impact is still doubtful, since residual concentrations increase organic matter content and represents a potential health hazard. This paper demonstrates a multiparametric study of two colloidal titration methods: spectrophotometric and zeta potential end point detection. The first one was optimized to guarantee the accuracy of cationic commercial PE quantification. It includes the indicator dose optimization using analytical criteria for competing equilibria, a calibration curve for two ranges of CPE concentration (1 - 5 ppm and 5 - 100 ppm) and the interference study of flocculant and Sn in the CPE quantification. The second method provides a physicochemical validation of the electric surface phenomena occurring during the colloidal titration and the end point detection. As an additional contribution the zeta potential titration was discussed and proposed as an alternative method for quantifying CPE when the sample is metal free.展开更多
Poly(diallyldimethylammonium chloride)(PDDA)is used as organic coagulant in water purification and auxiliary agent in paper production.Determination of PDDA in aqueous solutions is carried out usually by means of poly...Poly(diallyldimethylammonium chloride)(PDDA)is used as organic coagulant in water purification and auxiliary agent in paper production.Determination of PDDA in aqueous solutions is carried out usually by means of polyelectrolyte titration using streaming current detector or o-Toluidine Blue dye for endpoint recognition.The proposed method of PDDA assay takes advantage of Coomassie Brilliant Blue G dye having strong affinity to cationic macromolecules.Titration of PDDA solution with the dye is carried out measuring absorbance at 585nm.Inflection points of the obtained zigzag photometric curves have good repeatability provided that titration rate is low enough to attain endpoint for 1hour or more.The method assures rectilinear calibration(R2=0.999 5)in the broad range of PDDA concentrations from 0.3to 9.6mg·dm^(-3).展开更多
文摘Flocculation studies between dual polymers on pulp and paper mill wastewater are reported in this paper. The effects of different molecular weights of polyDADMAC and different dosages of Polyacrylamide (PAM) were studied. The molecular weights of polyDADMAC used were 8.8×104, 10.5×104 and 15.7×104 g/mol. The flocculation performance was analyzed in jar tests with PolyDADMAC and Polyacrylamide dosages ranging from 0.4-2.0 mg/L﹣1 and 0.4-8.0 mg/L﹣1 respectively. A higher molecular weight and a 6.0 mg/L﹣1 dosagepolyDADMAC gave the highest level of flocculation based on turbidity and TSS removal. In addition, increasing the molecular weight of PolyDADMAC increased ζ potential values approaching zero. This indicated that polyDADMAC acts as a destabilizer. Based on TSS, the addition of PAM will improve the size of microflocs created by polyDADMAC. It demonstrates that PAM acts as a bridger between microflocs.
文摘In water treatment processes and conditioning drinking water, PEs are widely used;however, their environmental impact is still doubtful, since residual concentrations increase organic matter content and represents a potential health hazard. This paper demonstrates a multiparametric study of two colloidal titration methods: spectrophotometric and zeta potential end point detection. The first one was optimized to guarantee the accuracy of cationic commercial PE quantification. It includes the indicator dose optimization using analytical criteria for competing equilibria, a calibration curve for two ranges of CPE concentration (1 - 5 ppm and 5 - 100 ppm) and the interference study of flocculant and Sn in the CPE quantification. The second method provides a physicochemical validation of the electric surface phenomena occurring during the colloidal titration and the end point detection. As an additional contribution the zeta potential titration was discussed and proposed as an alternative method for quantifying CPE when the sample is metal free.
文摘Poly(diallyldimethylammonium chloride)(PDDA)is used as organic coagulant in water purification and auxiliary agent in paper production.Determination of PDDA in aqueous solutions is carried out usually by means of polyelectrolyte titration using streaming current detector or o-Toluidine Blue dye for endpoint recognition.The proposed method of PDDA assay takes advantage of Coomassie Brilliant Blue G dye having strong affinity to cationic macromolecules.Titration of PDDA solution with the dye is carried out measuring absorbance at 585nm.Inflection points of the obtained zigzag photometric curves have good repeatability provided that titration rate is low enough to attain endpoint for 1hour or more.The method assures rectilinear calibration(R2=0.999 5)in the broad range of PDDA concentrations from 0.3to 9.6mg·dm^(-3).
