The aim of the present work was to produce a polyaluminium ferric silicate chloride （PAFSiC） coagulant from acidic and alkaline wastewater of purifying graphite by roasting, and subsequently to evaluate coagulation ...The aim of the present work was to produce a polyaluminium ferric silicate chloride （PAFSiC） coagulant from acidic and alkaline wastewater of purifying graphite by roasting, and subsequently to evaluate coagulation efficiency of the reagent by treating surface water from the Yellow River as well as municipal wastewater in comparison with the conventional coagulant polyaluminium chloride （PAC）. The PAFSiC coagulant was prepared by co-polymerization. The effects of （Al＋Fe）/Si molar ratio, OH/（Al＋Fe） molar ratio （i.e., γ value）, coagulant dosage and pH value of test suspension on the coagulation behavior of FAFSiC and the stability of the PAFSiC were also examined. Results showed that PAFSiC performed more efficiently than PAC in removing turbidity, chemical oxygen demand （COD）, and total phosphate （TP）. The PAFSiC with a γ value of 2.0 and （Al＋Fe）/Si ratio of 5 （PAFSiC 2.0/5） showed excellent coagulation effect for both turbidity and COD, while PAFSiC 1.0/5 was the best for TP. The optimum coagulation pH range of PAFSiC 2.0/5 was 5.0–9.0, slightly wider than that of PAC （6.0–8.0）. The process can be easily incorporated into high-purity graphite production plants, thereby reducing wastewater pollution and producing a valuable coagulant.展开更多
Crystal structure of a novel hydrated tridecameric polyaluminium chloride, [Al13（μ3-OH）6（μ2-OH）6（μ2-OH）12（H2O）24] Cl15·13H2O, has been determined by X-ray structure analysis, obtaining the detailed str...Crystal structure of a novel hydrated tridecameric polyaluminium chloride, [Al13（μ3-OH）6（μ2-OH）6（μ2-OH）12（H2O）24] Cl15·13H2O, has been determined by X-ray structure analysis, obtaining the detailed structural parameters and structure features. Moreover, the formation course was also discussed. The crystal belongs to monoclinic system, space group P21/c, with a = 1.3912（2）, b = 2.3529（3）, c = 2.2395（2） nm, β= 90.407（2）°, V = 7.3307（14） nm^3, Z = 4, Dc = 1.773 g/cm^3, F（000） = 4040, GOOF = 1.050,μ（MoKα）= 0.829 mm^-1, the final R = 0.0506 and wR = 0.1453 for 10553 observed reflections with I〉 2σ（I）. The structure of polycation of the title compound is different from either Keggin-type Al13 consisting of a central tetrahedral AlO4 core surrounded by twelve octahedral AlO6 units through corner-sharing or the ＂three hexameric rings juxtaposed＂ side by side predicted by ＂Core-Links＂ model linked by thirteen octahedral AlO6 units through edge-sharing. It has a ＂tortoise-like＂ structure with turnup ＂forefeet＂ and ＂tail＂, that is, an octahedral AlO6 core is surrounded by a ＂hexameric ring＂ through edge-sharing, then six octahedral AlO6 units are suspended onto the periphery of the ring upper and lower alternately by sharing two neighboring corners with an average turn angle of 21° entad. This kind of hydrated tridecameric polyaluminium chloride with such form is very important to further understand the existing forms and transformation rules of aluminium ion in hydrolysis system of its salts, speculate the process and mechanism of various hydrolysis and polymerization forms from Al（H2O）6^3＋ to Al（OH）3, and establish the relationship between structure and properties.展开更多
This research was aimed at investigating the reduction of DOM fractions and their trihalomethane formation potential （THMFP） by in-line coagulation with 0.1 μm ceramic membrane filtration. The combination of cerami...This research was aimed at investigating the reduction of DOM fractions and their trihalomethane formation potential （THMFP） by in-line coagulation with 0.1 μm ceramic membrane filtration. The combination of ceramic membrane filtration with a coagulation process is an alternative technology which can be applied to enhance conventional coagulation processes in the field of water treatment and drinking water production. The Ping River water （high turbidity water） was selected as the raw surface water because it is currently the main raw water source for water supply production in the urban and rural areas of Chiang Mai Province. From the investigation, the results showed that the highest percent reductions of DOC, UV-254, and THMFP （47.6%, 71.0%, and 67.4%, respectively） were achieved from in-line coagulation with ceramic membrane filtration at polyaluminum chloride dosage 40 mg/L. Resin adsorption techniques were employed to characterize the DOM in raw surface water and filtered water. The results showed that the use of a ceramic membrane with in-line coagulation was able to most efficiently reduce the hydrophobic fraction （HPOA） （68.5%）, which was then followed by the hydrophilic fraction （HPIA） （49.3%）. The greater mass DOC reduction of these two fractions provided the highest THMFP reductions （55.1% and 37.2%, respectively）. Furthermore, the in-line coagulation with ceramic membrane filtration was able to reduce the hydrophobic （HPOB） fraction which is characterized by high reactivity toward THM formation. The percent reduction of mass DOC and THMFP of HPOB by in-line coagulation with ceramic membrane filtration was 45.9% and 48.0%, respectively.展开更多
A high flocculation performance composite flocculant was prepared with sodium alginate, polyaluminium ferric chloride and cationic polyacrylamide. And the composite flocculant was used in papermaking wastewater treatm...A high flocculation performance composite flocculant was prepared with sodium alginate, polyaluminium ferric chloride and cationic polyacrylamide. And the composite flocculant was used in papermaking wastewater treatment. Results indicated that it achieve the best flocculation performance when the raw material mass ratio was 2:1:1, the dosage of the composite flocculant was 20 mg/L, and the removal efficiency of COD and turbidity with this composite flocculant reached 89.6% and 99.2%, respectively.展开更多
To compare the treatment effects and the costs of coagulation/Fenton process and Fenton/coagulation process in leachate treatment,fresh and old leachates were respestively treated with these two techniques.The experim...To compare the treatment effects and the costs of coagulation/Fenton process and Fenton/coagulation process in leachate treatment,fresh and old leachates were respestively treated with these two techniques.The experimental results indicate that the highest chemical oxygen demand(COD)removal rate of Fenton reaction on leachate can be acquired under the conditions of pH=3.5,nH2O2/nFe2+=6,mH2O2/mCOD=3,and reaction time=4 h.Polyaluminium chloride(PAC)coagulation has the highest COD removal rate on leachate under the condition of mPAC/mCOD=0.6.Under the optimum reaction conditions,coagulation/Fenton and Fenton/coagulation processes were respestively adopted to treat raw leachate.The data also show that COD removal rate of coagulation/Fenton process on fresh and old leachates are 90.56% and 86.52% respectively and that of Fenton/coagulation process 89.99% and 85.99%,so there is no obvious difference.But the cost of coagulation/Fenton process for leachate treatment is RMB 62.6,lower than that of Fenton/coagulation process.Therefore,coagulation/Fenton process is more optimized than Fenton/coagulation process for leachate treatment.展开更多
The effects of the coagulation-flocculation process using polyaluminium chloride (PAC) and its aids on the removal of organics and nutrient in the combined sewage from Shanghai Zhuyuan First Municipal Wastewater Treat...The effects of the coagulation-flocculation process using polyaluminium chloride (PAC) and its aids on the removal of organics and nutrient in the combined sewage from Shanghai Zhuyuan First Municipal Wastewater Treatment Plant are studied. The coagulant aids include cationic polyacrylamide (PAM), polyvinyl alcohol (PVA), activated silica (AS) and a kind of polyelectrolyte called AN prepared by the authors. The coagulating solution was added to the glass jar holding 1 L wastewater and stirred to a uniform mixture which was stilled to let the supernatant turn out. The supernatant was analyzed to see the removal efficiencies of suspended solid (SS), chemical oxygen demand (COD), soluble chemical oxygen demand (S-COD), total phosphorus (TP) and orthophosphate (PO4 -P). It is found that PAC is efficient in reducing those five matters, PAM, PVA and 3? AN each faciliates the reduction of TP, SS, COD and S-COD and has little contribution to the removal of ammonia nitrigen and orthophosphate, and AS is noneffective at all. The coagulation-flocculation process with PAC has demonstrated applicable to the treatment of combined sewage in Shanghai, and it involves mainly the sweep coagulation mechanism and maybe some more complicated mechanism as well.展开更多
基金supported by the National Natural Science Foundation of China (No. 20971112)the Major Public Service Project of Henan Province (No. 101100910300)+1 种基金the Natural Science Research Pro- gram of Education Department in Henan Province (No. 2011A610012)the Science and Technology Program of Zhengzhou City (No. 10PTGG339-4)
文摘The aim of the present work was to produce a polyaluminium ferric silicate chloride （PAFSiC） coagulant from acidic and alkaline wastewater of purifying graphite by roasting, and subsequently to evaluate coagulation efficiency of the reagent by treating surface water from the Yellow River as well as municipal wastewater in comparison with the conventional coagulant polyaluminium chloride （PAC）. The PAFSiC coagulant was prepared by co-polymerization. The effects of （Al＋Fe）/Si molar ratio, OH/（Al＋Fe） molar ratio （i.e., γ value）, coagulant dosage and pH value of test suspension on the coagulation behavior of FAFSiC and the stability of the PAFSiC were also examined. Results showed that PAFSiC performed more efficiently than PAC in removing turbidity, chemical oxygen demand （COD）, and total phosphate （TP）. The PAFSiC with a γ value of 2.0 and （Al＋Fe）/Si ratio of 5 （PAFSiC 2.0/5） showed excellent coagulation effect for both turbidity and COD, while PAFSiC 1.0/5 was the best for TP. The optimum coagulation pH range of PAFSiC 2.0/5 was 5.0–9.0, slightly wider than that of PAC （6.0–8.0）. The process can be easily incorporated into high-purity graphite production plants, thereby reducing wastewater pollution and producing a valuable coagulant.
基金Project supported by NNSFC (No. 20563002), NSF of Inner Mongolia Autonomous Region (200508010204) and Key Item Foundation of Education Committee of Inner Mongolia Autonomous Region (ZD01070)
文摘Crystal structure of a novel hydrated tridecameric polyaluminium chloride, [Al13（μ3-OH）6（μ2-OH）6（μ2-OH）12（H2O）24] Cl15·13H2O, has been determined by X-ray structure analysis, obtaining the detailed structural parameters and structure features. Moreover, the formation course was also discussed. The crystal belongs to monoclinic system, space group P21/c, with a = 1.3912（2）, b = 2.3529（3）, c = 2.2395（2） nm, β= 90.407（2）°, V = 7.3307（14） nm^3, Z = 4, Dc = 1.773 g/cm^3, F（000） = 4040, GOOF = 1.050,μ（MoKα）= 0.829 mm^-1, the final R = 0.0506 and wR = 0.1453 for 10553 observed reflections with I〉 2σ（I）. The structure of polycation of the title compound is different from either Keggin-type Al13 consisting of a central tetrahedral AlO4 core surrounded by twelve octahedral AlO6 units through corner-sharing or the ＂three hexameric rings juxtaposed＂ side by side predicted by ＂Core-Links＂ model linked by thirteen octahedral AlO6 units through edge-sharing. It has a ＂tortoise-like＂ structure with turnup ＂forefeet＂ and ＂tail＂, that is, an octahedral AlO6 core is surrounded by a ＂hexameric ring＂ through edge-sharing, then six octahedral AlO6 units are suspended onto the periphery of the ring upper and lower alternately by sharing two neighboring corners with an average turn angle of 21° entad. This kind of hydrated tridecameric polyaluminium chloride with such form is very important to further understand the existing forms and transformation rules of aluminium ion in hydrolysis system of its salts, speculate the process and mechanism of various hydrolysis and polymerization forms from Al（H2O）6^3＋ to Al（OH）3, and establish the relationship between structure and properties.
基金the Center of Excellence on Hazardous Substance Management,Chulalongkorn University,Bangkok,Thailand for financial support
文摘This research was aimed at investigating the reduction of DOM fractions and their trihalomethane formation potential （THMFP） by in-line coagulation with 0.1 μm ceramic membrane filtration. The combination of ceramic membrane filtration with a coagulation process is an alternative technology which can be applied to enhance conventional coagulation processes in the field of water treatment and drinking water production. The Ping River water （high turbidity water） was selected as the raw surface water because it is currently the main raw water source for water supply production in the urban and rural areas of Chiang Mai Province. From the investigation, the results showed that the highest percent reductions of DOC, UV-254, and THMFP （47.6%, 71.0%, and 67.4%, respectively） were achieved from in-line coagulation with ceramic membrane filtration at polyaluminum chloride dosage 40 mg/L. Resin adsorption techniques were employed to characterize the DOM in raw surface water and filtered water. The results showed that the use of a ceramic membrane with in-line coagulation was able to most efficiently reduce the hydrophobic fraction （HPOA） （68.5%）, which was then followed by the hydrophilic fraction （HPIA） （49.3%）. The greater mass DOC reduction of these two fractions provided the highest THMFP reductions （55.1% and 37.2%, respectively）. Furthermore, the in-line coagulation with ceramic membrane filtration was able to reduce the hydrophobic （HPOB） fraction which is characterized by high reactivity toward THM formation. The percent reduction of mass DOC and THMFP of HPOB by in-line coagulation with ceramic membrane filtration was 45.9% and 48.0%, respectively.
文摘A high flocculation performance composite flocculant was prepared with sodium alginate, polyaluminium ferric chloride and cationic polyacrylamide. And the composite flocculant was used in papermaking wastewater treatment. Results indicated that it achieve the best flocculation performance when the raw material mass ratio was 2:1:1, the dosage of the composite flocculant was 20 mg/L, and the removal efficiency of COD and turbidity with this composite flocculant reached 89.6% and 99.2%, respectively.
基金National Key Project of Water Pollution Control and Treatment Technology,China(No.2008ZX0720700902)
文摘To compare the treatment effects and the costs of coagulation/Fenton process and Fenton/coagulation process in leachate treatment,fresh and old leachates were respestively treated with these two techniques.The experimental results indicate that the highest chemical oxygen demand(COD)removal rate of Fenton reaction on leachate can be acquired under the conditions of pH=3.5,nH2O2/nFe2+=6,mH2O2/mCOD=3,and reaction time=4 h.Polyaluminium chloride(PAC)coagulation has the highest COD removal rate on leachate under the condition of mPAC/mCOD=0.6.Under the optimum reaction conditions,coagulation/Fenton and Fenton/coagulation processes were respestively adopted to treat raw leachate.The data also show that COD removal rate of coagulation/Fenton process on fresh and old leachates are 90.56% and 86.52% respectively and that of Fenton/coagulation process 89.99% and 85.99%,so there is no obvious difference.But the cost of coagulation/Fenton process for leachate treatment is RMB 62.6,lower than that of Fenton/coagulation process.Therefore,coagulation/Fenton process is more optimized than Fenton/coagulation process for leachate treatment.
文摘The effects of the coagulation-flocculation process using polyaluminium chloride (PAC) and its aids on the removal of organics and nutrient in the combined sewage from Shanghai Zhuyuan First Municipal Wastewater Treatment Plant are studied. The coagulant aids include cationic polyacrylamide (PAM), polyvinyl alcohol (PVA), activated silica (AS) and a kind of polyelectrolyte called AN prepared by the authors. The coagulating solution was added to the glass jar holding 1 L wastewater and stirred to a uniform mixture which was stilled to let the supernatant turn out. The supernatant was analyzed to see the removal efficiencies of suspended solid (SS), chemical oxygen demand (COD), soluble chemical oxygen demand (S-COD), total phosphorus (TP) and orthophosphate (PO4 -P). It is found that PAC is efficient in reducing those five matters, PAM, PVA and 3? AN each faciliates the reduction of TP, SS, COD and S-COD and has little contribution to the removal of ammonia nitrigen and orthophosphate, and AS is noneffective at all. The coagulation-flocculation process with PAC has demonstrated applicable to the treatment of combined sewage in Shanghai, and it involves mainly the sweep coagulation mechanism and maybe some more complicated mechanism as well.
