ABSTRACT
The capabilities and performance of γ-titanium phosphate (γ-TiP) with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as a latent thermal catalyst were investigated by the copolymerization of glycidyl phenyl ether (GPE) and hexahydro-4-methylphthalic anhydride (MHHPA) at different temperatures for a period of one hour. Polymerization was not observed until the reactants were heated to 100 °C. Upon increasing the temperature to 120 °C, the conversion in the presence of γ-TiP·DBU as a catalyst showed 98% conversion in 1 h. The thermal stability of GPE and MHHPA reacted in the presence of γ-TiP·DBU at 40 °C for 144 h resulted in less than 7% conversion of GPE. The conversion of GPE did not show a significant increase at 40 °C.
ABSTRACT
In this study, a higher concentration of (reactive dyestuff and salt) mixed water was used to verify the feasibility of separation by membrane techniques. The commercial nano filtration ceramic membrane (MWCO 200 Da) has been used in cross flow mode for separation of dyes and salts from highly concentrated mixed water solution. NF ceramic membrane presents good permeability (pure water flux 54.15 Lm-2 h-1, TMP 8 bar), 8% dye rejection and reduced salt rejection of NaCl (<8%) and Na2SO4 (<25%). Consequently, the operation parameters (TMP, temperature) and solution environment (solution pH, salt concentration and dye concentration) have been intensively evaluated for separation efficiency in the NF ceramic membrane process. Significantly, the NF ceramic membrane has performed less rejection to chloride ions than sulphate ions due to the Donnan effect. Solution pH, concentration of salt and dye concentration have shown significant effects on ceramic membrane separation performance. In addition, pollutant removals were achieved with noteworthy values for the chemical oxygen demand for permeate solution also color difference between concentrate and permeate. In conclusion, the strong rejection of dyes by the NF ceramic membranes proves that it can be suitable alternatives for textile wastewater treatment process.
ABSTRACT
Dyeing and fastness properties of a series of 4-fluorosulfonylphenylazo-5-pyrazolone dyes on polyester were investigated in this study. The 4-nitrophenylazo-5-pyrazolone dyes were also synthesized to compare their dyeing and fastness properties on polyester with those of fluorosulfonyl-substituted analogues. The substantivity of 4-arylazo-5-pyrazolone derivatives containing a p-fluorosulfonyl group in the diazo component was lower than that of their nitro analogues which have a higher extinction coefficient and higher affinity because of the polar nitro group. They showed relatively hypsochromic color and lower chroma on polyester compared with their nitro analogues because of the relatively weaker electron-accepting power of the fluorosulfonyl group compared to the nitro group. Disperse dyeing of polyester with 4-fluorosulfonylphenylazo-5-pyrazolone disperse dyes achieved high color fastness and reduces the adverse environmental impact of the dyeing process by providing the option of performing alkali clearing instead of reductive clearing, which has high biological oxygen demand when discharged into the dyeing effluent and generates carcinogenic aromatic amines.
