betadex and potassium-persulfate

A new terpolymer named β-CD-MA-SSS was produced using free-radical polymerization of β-cyclodextrin (β-CD), maleic-anhydride (MA) and sodium-styrene-sulfonate (SSS) as monomers, with potassium persulfate (KPS) as initiator. Its performance as a scale inhibitor to prevent deposition of calcium carbonate (CaCO3) has been investigated. Experimental results demonstrated that β-CD-MA-SSS performed excellent scale inhibition and exhibited a high conversion rate under the following conditions: initiator consisting of 6%, molar ratio of reaction monomers SSS:MA = 0.8:1, MA:β-CD = 6:1, reaction temperature of 80 °C, reaction time of 6 h, and dropping time of 40 min when MA was dosed as a substrate, and SSS and KPS were dosed as dropping reactants simultaneously. Use of a Fourier transform infrared spectrometer for this inhibitor showed that the polymerization reaction had taken place with the reaction monomers under the above specified conditions. Scanning electron microscopy indicated that the β-CD-MA-SSS had a strong chelating ability for calcium (Ca(2+)) and a good dispersion ability for calcium carbonate (CaCO3).

Topics: beta-Cyclodextrins; Catalysis; Maleic Anhydrides; Microscopy, Electron, Scanning; Polymerization; Polymers; Polystyrenes; Potassium Compounds; Sulfates; Sulfonic Acids; Temperature

To enhance the catalytic oxidation of pentachlorophenol (PCP) in contaminated soil suspensions using tetra(p-sulfophenyl)porphineiron(III) (Fe(III)-TPPS) as a catalyst and potassium monopersulfate (KHSO(5)) as the single-oxygen donor, the effect of added hydroxypropyl-beta-cyclodextrin (HP-beta-CD) was examined. At pH 4 and 6, the percentage of PCP disappearance increased substantially in the presence of HP-beta-CD. In addition, the self-degradation of Fe(III)-TPPS was significantly retarded in the presence of HP-beta-CD. This retarded self-degradation can be attributed to the stabilization of Fe(III)-TPPS via the formation of a supramolecular complex with HP-beta-CD. The kinetic constant for the self-degradation of Fe(III)-TPPS in the presence of HP-beta-CD at pH 6 was much smaller than that at pH 4, indicating that Fe(III)-TPPS is more stable at pH 6. Thus, the amount of Fe(III)-TPPS, KHSO(5) and HP-beta-CD required to degrade PCP in contaminated soil suspensions was optimal at pH 6. When PCP-contaminated soil suspensions were treated under the optimized conditions, 12-18% and 24-28% of the PCP was mineralized to CO(2) in the absence and presence of HP-beta-CD, respectively. These results show that the presence of HP-beta-CD in the Fe(III)-TPPS/KHSO(5) catalytic system is effective in enhancing the degradation of PCP in contaminated soil suspensions.

Topics: 2-Hydroxypropyl-beta-cyclodextrin; beta-Cyclodextrins; Catalysis; Environmental Restoration and Remediation; Hydrogen-Ion Concentration; Oxidation-Reduction; Pentachlorophenol; Porphyrins; Potassium Compounds; Soil Pollutants; Sulfates

A novel biomimetic catalytic system containing a supramolecular complex between iron(III)-tetrakis(p-sulfonatophenyl)porphyrin [Fe(III)-TPPS] and hydroxypropyl-beta-cyclodextrin (HP-beta-CD) was examined for the potassium monopersulfate catalyzed oxidation of pentachlorophenol (PCP). In the absence of HP-beta-CD, the percentage of PCP disappearance and the numbers of chlorine atoms released from PCP increased to 50% and 1.5 for a 1-day reaction period, respectively. However, in the presence of HP-beta-CD, the PCP completely disappeared and the number of chlorine atoms from PCP was increased to 3.1. o-Tetrachloroquinone, 2- and 4-hydroxyl-nonachlorodiphenyl ethers, and octachlorodibenzo-p-dioxin were detected among the oxidation products. In the absence of HP-beta-CD, the percentage of PCP conversion to oxidation products increased and then reached plateau. In the presence of HP-beta-CD, the amount of oxidation products produced initially increased for the first 10 min and thereafter decreased gradually. These results suggest that the addition of HP-beta-CD results in the further degradation of oxidation products. In addition, the mineralization of PCP to CO2 was investigated using 14C6-labeled PCP. After a 1-day reaction period, 24% of the 14C6-labeled PCP was converted to 14CO2 in the presence of HP-beta-CD, although significant 14CO2 generation was not observed in its absence. The effect of HP-beta-CD on the facilitation of PCP degradation can be attributed to the fact that the self-oxidation of Fe(III)-TPPS is prevented by the formation of a stable supramolecular complex between HP-beta-CD and Fe(III)-TPPS.

Topics: 2-Hydroxypropyl-beta-cyclodextrin; beta-Cyclodextrins; Carbon Dioxide; Ferric Compounds; Pentachlorophenol; Porphyrins; Potassium Compounds; Spectrophotometry, Ultraviolet; Sulfates