The effect of hydraulic retention time (HRT) and pH on the biooxidation of ferrous iron during simulated acid mine drainage (AMD) treatment was investigated.The simulated AMD was highly acidic (pH 2.5), rich in iron (...The effect of hydraulic retention time (HRT) and pH on the biooxidation of ferrous iron during simulated acid mine drainage (AMD) treatment was investigated.The simulated AMD was highly acidic (pH 2.5), rich in iron (about 1700 mg/L) and copper (about 200 mg/L), and contained high concentrations of sulfate (about 4700 mg/L).The biooxidation of ferrous iron was studied in a laboratory-scale upflow packed bed bioreactor (PBR).The HRT was shortened stepwise from 40 h to 20 h, 13 h, and 8 h under the acidic environment at a pH value of 2.2.Then, the influent pH value was changed from 2.2 to 1.2 at a constant suitable HRT.Physiochemical and microbial community structure analyses were performed on water samples and stuffing collected from the bioreactor under different conditions.The results indicate that the efficiency of ferrous iron oxidation gradually decreased with the decrease of HRT, and when the HRT exceeded 13 h, ferrous iron in AMD was almost completely oxidized.In addition, the best efficiency of ferrous iron oxidation was achieved at the influent pH value of 1.8.Microbial community structure analyses show that Leptospirillum is the predominant genus attached in the bioreactor, and low influent pH values are suitable for the growth of Leptospirillum.展开更多
In this paper it was studied that these dosage effects of CPAM, cationic starch?boron modified silica sol(BMS), Al2(SO4)3, pH value and electrolyte on the retention and drainage of different microparticulate systems i...In this paper it was studied that these dosage effects of CPAM, cationic starch?boron modified silica sol(BMS), Al2(SO4)3, pH value and electrolyte on the retention and drainage of different microparticulate systems including CPAM, cationic starch and boron silica sol. The research results indicated that CPAM had no good retention when used with boron silica sol. The best retention efficiency was the microparticulate system of CPAM + cationic starch with boron modified silica sol; Secondly was that of cationic starch with boron modified silica sol; The worst was that of CPAM with boron modified silica sol. The retention efficiency had no relation with the addition order between CPAM and cationic starch. It was also found that the microparticulate retention system of boron modified silica sol could be used in alum-rosin sizing and in acidity, neutral or alkaline papermaking conditions. This system also could be used with close circulate water so that it could reduce the water pollution and waste.展开更多
This paper deals with the retention and drainage properties of the high substituted degree cationic starch (HCS) prepared by half-dry process. The experiments show that HCS has remarkable effects on filler retention a...This paper deals with the retention and drainage properties of the high substituted degree cationic starch (HCS) prepared by half-dry process. The experiments show that HCS has remarkable effects on filler retention and drainage in papermaking industry. With the degree of substitution (DS) of HCS increasing, the effects on filler retention and drainage increase. When the DS of HCS is 0.509 and the dosage is 0.08%, the freeness decreases about 12oSR and the filler retention is 79.82%.展开更多
The conditions of preparation and performance of a new structure of cationic organic polymeric micropaticles (CPMP) mainly composed of styrene and DADMAC were studied. And its application on retention and drainage on ...The conditions of preparation and performance of a new structure of cationic organic polymeric micropaticles (CPMP) mainly composed of styrene and DADMAC were studied. And its application on retention and drainage on bleached hardwood pulp was investigated and compared with that of APAM and CPAM. The results show that the retention and drainage of CPMP on pulp is in positive proportion to the rise of the potential of the solution, and the first-pass retention ratio of bleached hardwood pulp goes up with the increase of the CPMP content. The functions of CPMP and CPAM are affected less by the shear force and the pH value of the system compared to that of APAM, and effect on retention of CPMP3 is appropriate to that of CPAM, but superior to that of APAM.展开更多
In this paper, a new type of retention system of PEO/cofactor retention system is introduced, the cofactors used are phenol-formaldehyde resin, wheat straw alkaline lignin and its derivatives such as hydroxymethylated...In this paper, a new type of retention system of PEO/cofactor retention system is introduced, the cofactors used are phenol-formaldehyde resin, wheat straw alkaline lignin and its derivatives such as hydroxymethylated lignin, sulfited lignin and lignin-based phenol-formaldehyde resin. The first pass retention of newsprint slurry and the properties of handsheet are improved by using the system. The results indicate that a new application field for lignin has been exploited.展开更多
AIM To compare outcomes after open simple prostatectomy without bladder irrigation, in subjects drained by combined 2-way urethral catheter and suprapubic catheter(SPC) vs those drained by 2-way urethral catheter only...AIM To compare outcomes after open simple prostatectomy without bladder irrigation, in subjects drained by combined 2-way urethral catheter and suprapubic catheter(SPC) vs those drained by 2-way urethral catheter only.METHODS A total of 84 participants undergoing Freyer's simple prostatectomy over an 18-mo period were randomized into 2 groups(n=42). Subjects in group 1 were managed with 2-way urethral catheter and in situ 2-way SPC while subjects in group 2 had a 2-way urethral catheter drainage only. In group 1 subjects, the SPC was spigotted and only used for drainage if there was clot retention. The primary outcomes were number of clot retention episodes, and number of clot retention episodes requiring bladder syringe evacuation. Other secondary outcomes evaluated were blood loss, requirement of extra analgesics, duration of surgery, hospital stay and presence or absence of post-op complications. RESULTS The mean age in the groups was 65.7(± 7.6) in group 1 vs 64.8(±6.8) in group 2.The groups were similar with respect to age, prostate specific antigen, prostate volume, blood loss, duration of surgery, blood transfusion and overall complication rate. However statistically significant differences were observed in clot retention episodes between group 1 and 2:0.8(±1.5)vs3.5(±4.4), P<0.000, clot retention episodes requiring evacuation with bladder syringe 0.4(± 0.9) vs 2.6(± 3.8), P = 0.001, requirement of extra analgesics 0.4(±0.5)vs4.0(±1.5), P<0.000 and duration of admission 8.6d(± 1.2) vs 7.3 CONCLUSION Subjects drained with a combination of urethral and SPCs have fewer clot retention episodes and reduced requirement of extra analgesics but slightly longer hospital stay.展开更多
The retention and drainage performances of microparticle retention system were studied in this paper, through measuring the improvement of beaten degree and retention ratio of slurry. The effects the retention system ...The retention and drainage performances of microparticle retention system were studied in this paper, through measuring the improvement of beaten degree and retention ratio of slurry. The effects the retention system on paper sheet were discussed by measuring physical properties of paper. Compared with the influence of Hydrocol system (CPAM/bentonite) on the aspects of retention aid and drainage properties as well as increased product cost per ton paper, the developed nonionic system has some superiority and better practicability.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.U1402234)the Guangxi Scientific Research and Technology Development Plan(Grants No.GuikeAB16380287 and GuikeAB17129025)+2 种基金the Public Welfare Fund of the Ministry of Environmental Protection of China(Grant No.201509049)the Program of International S & T Cooperation(Grant No.2016YFE0130700)the Fund of the General Research Institute for Nonferrous Metals(Grants No.53321 and 53348)
文摘The effect of hydraulic retention time (HRT) and pH on the biooxidation of ferrous iron during simulated acid mine drainage (AMD) treatment was investigated.The simulated AMD was highly acidic (pH 2.5), rich in iron (about 1700 mg/L) and copper (about 200 mg/L), and contained high concentrations of sulfate (about 4700 mg/L).The biooxidation of ferrous iron was studied in a laboratory-scale upflow packed bed bioreactor (PBR).The HRT was shortened stepwise from 40 h to 20 h, 13 h, and 8 h under the acidic environment at a pH value of 2.2.Then, the influent pH value was changed from 2.2 to 1.2 at a constant suitable HRT.Physiochemical and microbial community structure analyses were performed on water samples and stuffing collected from the bioreactor under different conditions.The results indicate that the efficiency of ferrous iron oxidation gradually decreased with the decrease of HRT, and when the HRT exceeded 13 h, ferrous iron in AMD was almost completely oxidized.In addition, the best efficiency of ferrous iron oxidation was achieved at the influent pH value of 1.8.Microbial community structure analyses show that Leptospirillum is the predominant genus attached in the bioreactor, and low influent pH values are suitable for the growth of Leptospirillum.
文摘In this paper it was studied that these dosage effects of CPAM, cationic starch?boron modified silica sol(BMS), Al2(SO4)3, pH value and electrolyte on the retention and drainage of different microparticulate systems including CPAM, cationic starch and boron silica sol. The research results indicated that CPAM had no good retention when used with boron silica sol. The best retention efficiency was the microparticulate system of CPAM + cationic starch with boron modified silica sol; Secondly was that of cationic starch with boron modified silica sol; The worst was that of CPAM with boron modified silica sol. The retention efficiency had no relation with the addition order between CPAM and cationic starch. It was also found that the microparticulate retention system of boron modified silica sol could be used in alum-rosin sizing and in acidity, neutral or alkaline papermaking conditions. This system also could be used with close circulate water so that it could reduce the water pollution and waste.
文摘This paper deals with the retention and drainage properties of the high substituted degree cationic starch (HCS) prepared by half-dry process. The experiments show that HCS has remarkable effects on filler retention and drainage in papermaking industry. With the degree of substitution (DS) of HCS increasing, the effects on filler retention and drainage increase. When the DS of HCS is 0.509 and the dosage is 0.08%, the freeness decreases about 12oSR and the filler retention is 79.82%.
文摘The conditions of preparation and performance of a new structure of cationic organic polymeric micropaticles (CPMP) mainly composed of styrene and DADMAC were studied. And its application on retention and drainage on bleached hardwood pulp was investigated and compared with that of APAM and CPAM. The results show that the retention and drainage of CPMP on pulp is in positive proportion to the rise of the potential of the solution, and the first-pass retention ratio of bleached hardwood pulp goes up with the increase of the CPMP content. The functions of CPMP and CPAM are affected less by the shear force and the pH value of the system compared to that of APAM, and effect on retention of CPMP3 is appropriate to that of CPAM, but superior to that of APAM.
文摘In this paper, a new type of retention system of PEO/cofactor retention system is introduced, the cofactors used are phenol-formaldehyde resin, wheat straw alkaline lignin and its derivatives such as hydroxymethylated lignin, sulfited lignin and lignin-based phenol-formaldehyde resin. The first pass retention of newsprint slurry and the properties of handsheet are improved by using the system. The results indicate that a new application field for lignin has been exploited.
文摘AIM To compare outcomes after open simple prostatectomy without bladder irrigation, in subjects drained by combined 2-way urethral catheter and suprapubic catheter(SPC) vs those drained by 2-way urethral catheter only.METHODS A total of 84 participants undergoing Freyer's simple prostatectomy over an 18-mo period were randomized into 2 groups(n=42). Subjects in group 1 were managed with 2-way urethral catheter and in situ 2-way SPC while subjects in group 2 had a 2-way urethral catheter drainage only. In group 1 subjects, the SPC was spigotted and only used for drainage if there was clot retention. The primary outcomes were number of clot retention episodes, and number of clot retention episodes requiring bladder syringe evacuation. Other secondary outcomes evaluated were blood loss, requirement of extra analgesics, duration of surgery, hospital stay and presence or absence of post-op complications. RESULTS The mean age in the groups was 65.7(± 7.6) in group 1 vs 64.8(±6.8) in group 2.The groups were similar with respect to age, prostate specific antigen, prostate volume, blood loss, duration of surgery, blood transfusion and overall complication rate. However statistically significant differences were observed in clot retention episodes between group 1 and 2:0.8(±1.5)vs3.5(±4.4), P<0.000, clot retention episodes requiring evacuation with bladder syringe 0.4(± 0.9) vs 2.6(± 3.8), P = 0.001, requirement of extra analgesics 0.4(±0.5)vs4.0(±1.5), P<0.000 and duration of admission 8.6d(± 1.2) vs 7.3 CONCLUSION Subjects drained with a combination of urethral and SPCs have fewer clot retention episodes and reduced requirement of extra analgesics but slightly longer hospital stay.
文摘The retention and drainage performances of microparticle retention system were studied in this paper, through measuring the improvement of beaten degree and retention ratio of slurry. The effects the retention system on paper sheet were discussed by measuring physical properties of paper. Compared with the influence of Hydrocol system (CPAM/bentonite) on the aspects of retention aid and drainage properties as well as increased product cost per ton paper, the developed nonionic system has some superiority and better practicability.
