Anaerobic treatment could effectively degrade organic chlorine. Reductive dechlorination mechanisms were confirmed through GC-MS analysis during anaerobic treatment of pulp bleachery effluents, the influence of sulfid...Anaerobic treatment could effectively degrade organic chlorine. Reductive dechlorination mechanisms were confirmed through GC-MS analysis during anaerobic treatment of pulp bleachery effluents, the influence of sulfide biologically produced and pH on the dechlorination revealed that nucleophilic substitution and alkaline hydrolysis were also nonbiological mechanisms.展开更多
Acid hydrogen peroxide catalyzed with molybdenum (PMo stage) is effective to decrease pulp kappa number and potentially minimize chlorine dioxide demand in subsequent ECF bleaching. This study aimed at developing cost...Acid hydrogen peroxide catalyzed with molybdenum (PMo stage) is effective to decrease pulp kappa number and potentially minimize chlorine dioxide demand in subsequent ECF bleaching. This study aimed at developing cost-effective methods for applying PMo as the first stage bleaching for eucalyptus kraft pulp and evaluating their impact on pulp properties and effluent quality in relation to current ECF bleaching techniques. The PMo(EP)DP and A/PMo(EP)DP sequences proved to be most cost-effective for PMo stage application. The pulp properties and effluent quality derived from bleaching with these two sequences were compared with those of the conventional bleaching with the DHT(EP)DP sequence. The PMo(EP)DP sequence produced pulp of refinability and physical properties similar to that of the reference but the A/PMo(EP)DP one resulted in pulp of 20% lower refinability and 10% lower tearing strength. Untreated effluents of the PMo(EP)DP and A/PMo(EP)DP sequences presented similar COD, but lower AOX and color than the DHT(EP)DP effluents. None of the effluents exhibited acute toxicity. The effluents from the PMo(EP)DP sequence showed much lower BOD and BOD/COD ratio than that of the A/PMo(EP)DP one. All effluents were readily treated in bench-scale reactors, and achieved COD removal efficiencies of greater than 70%.展开更多
The pulp and paper industry produces a large amount of colored effluent in the pulping,bleaching,and papermaking processes.The wastewater from the pulp washing and bleaching stages is also known as mid-stage pulping e...The pulp and paper industry produces a large amount of colored effluent in the pulping,bleaching,and papermaking processes.The wastewater from the pulp washing and bleaching stages is also known as mid-stage pulping effluent,which is difficult to treat due to its toxicity and dark dolor.This paper reports a novel Fe/C micro-electrolysis process for the treatment of the mid-stage pulping effluent.Results show that this process is effective in removing the color under optimal reaction conditions.Scanning electron microscopy(SEM)and Fourier transform infrared spectroscopy(FTIR)analyses indicate that the colored pollutants were removed from the wastewater in the Fe/C micro-electrolysis by adsorption,collection and filtration mechanisms.The Fe2+ions produced in the micro-electrolysis process functioned as Fenton’s reagents with H2O2 in the follow-up oxidation stage,which enhanced the removal of chemical oxygen demand(COD)and color.展开更多
In this study,allelochemicals were extracted from pulping effluents rather than from the raw ma-terial of plants.Herein,five organic solvents(ethyl acetate(EAC),methyl tert-butyl ether(MTBE),dichloromethane(DCM),carbo...In this study,allelochemicals were extracted from pulping effluents rather than from the raw ma-terial of plants.Herein,five organic solvents(ethyl acetate(EAC),methyl tert-butyl ether(MTBE),dichloromethane(DCM),carbon tetrachloride(CTC),and petroleum(PE))were applied to sep-arately extracting the allelochemicals from alkaline peroxide mechanical pulp(APMP)effluents.The results from the algal density,inhibition ratio,and optical density of 446 nm(OD 446nm)concluded that the extractives from the APMP effluents can act as effective allelochemicals and showed noticeable allelopathic inhibition effects on Microcystis aeruginosa growth.The results in-dicated that organic solvent extraction could be a practical approach to isolate the allelochemicals from the APMP effluents,which would broaden the potential application of the APMP effluents in the production of antimicrobial agents and other value-added materials.展开更多
文摘Anaerobic treatment could effectively degrade organic chlorine. Reductive dechlorination mechanisms were confirmed through GC-MS analysis during anaerobic treatment of pulp bleachery effluents, the influence of sulfide biologically produced and pH on the dechlorination revealed that nucleophilic substitution and alkaline hydrolysis were also nonbiological mechanisms.
文摘Acid hydrogen peroxide catalyzed with molybdenum (PMo stage) is effective to decrease pulp kappa number and potentially minimize chlorine dioxide demand in subsequent ECF bleaching. This study aimed at developing cost-effective methods for applying PMo as the first stage bleaching for eucalyptus kraft pulp and evaluating their impact on pulp properties and effluent quality in relation to current ECF bleaching techniques. The PMo(EP)DP and A/PMo(EP)DP sequences proved to be most cost-effective for PMo stage application. The pulp properties and effluent quality derived from bleaching with these two sequences were compared with those of the conventional bleaching with the DHT(EP)DP sequence. The PMo(EP)DP sequence produced pulp of refinability and physical properties similar to that of the reference but the A/PMo(EP)DP one resulted in pulp of 20% lower refinability and 10% lower tearing strength. Untreated effluents of the PMo(EP)DP and A/PMo(EP)DP sequences presented similar COD, but lower AOX and color than the DHT(EP)DP effluents. None of the effluents exhibited acute toxicity. The effluents from the PMo(EP)DP sequence showed much lower BOD and BOD/COD ratio than that of the A/PMo(EP)DP one. All effluents were readily treated in bench-scale reactors, and achieved COD removal efficiencies of greater than 70%.
文摘The pulp and paper industry produces a large amount of colored effluent in the pulping,bleaching,and papermaking processes.The wastewater from the pulp washing and bleaching stages is also known as mid-stage pulping effluent,which is difficult to treat due to its toxicity and dark dolor.This paper reports a novel Fe/C micro-electrolysis process for the treatment of the mid-stage pulping effluent.Results show that this process is effective in removing the color under optimal reaction conditions.Scanning electron microscopy(SEM)and Fourier transform infrared spectroscopy(FTIR)analyses indicate that the colored pollutants were removed from the wastewater in the Fe/C micro-electrolysis by adsorption,collection and filtration mechanisms.The Fe2+ions produced in the micro-electrolysis process functioned as Fenton’s reagents with H2O2 in the follow-up oxidation stage,which enhanced the removal of chemical oxygen demand(COD)and color.
基金supported by Tianjin Research Program of Application Foundation and Advanced Technology(No.14JCZDJC40500)National Undergraduate Innovation Program(No.2016100570039).
文摘In this study,allelochemicals were extracted from pulping effluents rather than from the raw ma-terial of plants.Herein,five organic solvents(ethyl acetate(EAC),methyl tert-butyl ether(MTBE),dichloromethane(DCM),carbon tetrachloride(CTC),and petroleum(PE))were applied to sep-arately extracting the allelochemicals from alkaline peroxide mechanical pulp(APMP)effluents.The results from the algal density,inhibition ratio,and optical density of 446 nm(OD 446nm)concluded that the extractives from the APMP effluents can act as effective allelochemicals and showed noticeable allelopathic inhibition effects on Microcystis aeruginosa growth.The results in-dicated that organic solvent extraction could be a practical approach to isolate the allelochemicals from the APMP effluents,which would broaden the potential application of the APMP effluents in the production of antimicrobial agents and other value-added materials.
