The use of Fenton＇s reagent （Fe^2＋/H2O2） and Fenton-like reagents containing transition metals of Cu（Ⅱ）, Zn（Ⅱ）, Co（Ⅱ）, and Mn（Ⅱ） for an alum sludge conditioning to improve its dewaterability was invest...The use of Fenton＇s reagent （Fe^2＋/H2O2） and Fenton-like reagents containing transition metals of Cu（Ⅱ）, Zn（Ⅱ）, Co（Ⅱ）, and Mn（Ⅱ） for an alum sludge conditioning to improve its dewaterability was investigated. The results obtained were compared with those obtained from conditioning the same alum sludge using cationic and anionic polymers. Experimental results show that Fenton＇s reagent was the best among the Fenton and Fenton-like reagents for the alum sludge conditioning. A considerable effectiveness of capillary suction time （CST） reduction efficiency of 47% can be achieved under test conditions of Fe^2＋/H2O2 = 20/125 mg/g DS （dry solid） and pH 6.0. The observation of floc-like particles after Fenton＇s reagent conditioning of alum sludge suggested that the mechanism of Fenton＇s reagent conditioning was different from that of polymer conditioning. In spite of the lower efficiency in the CST reduction of Fenton＇s reagent in alum sludge conditioning compared to that of polymer conditioning, Fenton＇s reagent offers a more environmentally safe option. Tiffs study provided an example of proactive treatment engineering, which is aimed at seeking a safe alternative to the use of polymers in sludge conditioning towards achieving a more sustainable sludge management strategy.展开更多
A coagulation-flocculation process is typically employed to treat the industrial wastewater generated by the consumer products industry manufacturing detergents, soaps, and others. The expenditure of chemicals includi...A coagulation-flocculation process is typically employed to treat the industrial wastewater generated by the consumer products industry manufacturing detergents, soaps, and others. The expenditure of chemicals including coagulants and chemicals for pH adjustment is costly for treating this wastewater. The objective of this study was to evaluate the feasibility of reusing the aluminum sulfate （alum） sludge as a coagulant or as a coagulation aid so that the fresh alum dosage can be minimized or the removal efficiency can be enhanced. The experiments were conducted in a jar-test apparatus simulating the coagulation-flocculation process for simultaneous removals of organic matters, anionic surfactants, suspended solids, and turbidity. At the optimum initial pH value of 10 and the fresh alum concentration of 400 mg/L, the total suspended solids （TSS）, total chemical oxygen demand （TCOD）, total anionic surfactants, and turbidity removal efficiencies were 71.5%, 76.4%, 95.4%, and 98.2%, respectively. The addition of alum sludge as a coagulant alone without any fresh alum addition could significantly remove the turbidity, TCOD, and anionic surfactants. The TSS was left in the supernatants after the settling period, but would subsequently be removed by adding the fresh alum. The TSS, TCOD, and turbidity removal efficiencies were also enhanced when both the alum sludge and the fresh alum were employed. The TCOD removal efficiency over 80% has been accomplished, which has never fulfilled by using the fresh alum alone. It is concluded that the alum sludge could be reused for the treatment of industrial wastewater generated by the consumer products industry.展开更多
As safe byproducts of drinking water treatment processes,ferric and alum water treatment residuals（FARs） have the potential to be new phosphate（P） immobilization materials.In this study,batch experiments were cond...As safe byproducts of drinking water treatment processes,ferric and alum water treatment residuals（FARs） have the potential to be new phosphate（P） immobilization materials.In this study,batch experiments were conducted to investigate and compare the adsorption characteristics of three P species by FARs.The results showed that the kinetic processes of different P species＇ adsorption by FARs could be described by a pseudo second-order model.The ranking list of the initial adsorption rates with respect to different phosphates was pyrophosphate,phytate,orthophosphate,hexametaphosphate and glycerophosphate.Of the six models considered,the two-site Langmuir model most effectively described the adsorption characteristics of the various P species.Upon fitting the results,the maximum adsorption capacities were determined to be 40.24 mg/g for phytate,18.04 mg/g for pyrophosphate,17.14 mg/g for orthophosphate,15.86 mg/g for hexametaphosphate and 10.81 mg/g for glycerophosphate.In addition,the adsorption processes of the different P species were spontaneous endothermic processes and were favored at lower pH values.The pH dependency was found to be especially true for orthophosphate,where the adsorption capacity decreased by 1.22 mg/g with an increase in pH from 5 to 9.Fractionation of the adsorbed P species from the FARs demonstrated that Al-P and Fe-P were the dominating forms,constituting approximately 80%-90% of the total P fractions,which indicated that the adsorbed P species had a low leaching risk and could stably exist in the FARs.Therefore,the FARs could be effective in controlling pollution in water caused by different P species.展开更多
The effects of addition of calcium hydroxide on aluminum sulphate （or alum） coagulation for removal of natural organic matter （NOM） and its subsequent effect on the formation potentials of two major types of regul...The effects of addition of calcium hydroxide on aluminum sulphate （or alum） coagulation for removal of natural organic matter （NOM） and its subsequent effect on the formation potentials of two major types of regulated disinfection byproducts （DBPs）, haloacetic acids （HAAs） and trihalomethanes （THMs）, have been examined. The results revealed several noteworthy phenomena. At the optimal coagulation pH （i.e. 6）, the coagulation behavior of NOM water solutions versus alum dose, showed large variation and a consequent great change in the formation potentials of the DBPs at certain coagulant doses. However, with addition of a relatively small amount of Ca（OH）2, although the zeta potential of coagulated floes remained almost the same, NOM removal became more consistent with alum dose. Importantly, also the detrimental effect of charge reversal on NOM removal at the low coagulant dose disappeared. This resulted in a steady decrease in the formation potentials of DBPs as a function of the coagulant dose. Moreover, the addition of Ca（OH）2 broadened the pH range of alum coagulation and promoted further reduction of the formation potentials of the DBPs. The enhancement effects of Ca（OH）2 assisted alum coagulation are especially pronounced at pH 7 and 8. Finally, synchronous fluorescence spectra showed that the reduction in DBPs formation potential by Ca（OH）2-assisted alum coagulation was connected to an enhanced removal of small hydrophobic and hydrophilic HA molecules. Ca（OH）2-assistance of alum coagulation appeared to increase substantially the removal of the hydrophilic HA fraction responsible for HAAs formation, prompting further reduction of HAA formation potentials.展开更多
Ferrate is an excellent water treatment agent for its multi functions in oxidation, disinfection, coagulation and adsorption, but its coagulation ability depends on its dosage and is after its oxidation. This paper f...Ferrate is an excellent water treatment agent for its multi functions in oxidation, disinfection, coagulation and adsorption, but its coagulation ability depends on its dosage and is after its oxidation. This paper focuses on preparing a new kind of ferrate combined with alum to enhance its coagulation function for water purification. An effective electrolysis reactor was designed and employed in the test. Some key parameters in the process of electrolysis concerning the preparation efficiency, such as the current density, temperature and alkalinity were also investigated. The proper conditions for ferrate alum preparation were determined. Under the condition of 5V given voltage, 6h electrolyzing interval, below 2% alum concentration (in weight), a combined liquid ferrate alum products was successfully prepared, which contained 0.0294 mol/L FeO 2- 4 and 0.0302 mol/L total soluble ferron with 2% Al 2O 3. There was no insoluble ferron produced by controlling an optimum electrochemical condition.展开更多
Generation of alum sludge(AS)at drinking water treatment plants represents an environmental liability and adds to the cost of water purification.Consequently,this study explored the feasibility of using low and high c...Generation of alum sludge(AS)at drinking water treatment plants represents an environmental liability and adds to the cost of water purification.Consequently,this study explored the feasibility of using low and high carbon containing alum sludge from two water treatment plants to synthesize zeolite LTA.The hypothesis was that zeolite LTA synthesis was dependant upon alum sludge source and that a range of strategies may be required to optimize zeolite crystallinity.Zeolite characteristics such as morphology,phase composition,crystallinity,and particle size distribution were recorded."One pot"hydrothermal synthesis of precursor gel with molar composition 4.2 Na2O:Al2O3:1.2 SiO_(2):168 H2O at 80℃ for 3 hr resulted in 25 and 46 wt.%zeolite LTA from high and low carbonaceous sludge,respectively.Prior to hydrothermal reaction stage it was discovered that ageing of the gel,addition of zeolite LTA seeds,ultrasonic treatment and calcination all promoted zeolite LTA formation.Calcination of the alum sludge at 700℃ for 2 hr before hydrothermal synthesis resulted in particle size reduction and the highest amount of crystalline zeolite LTA:79 wt.%from low carbon sludge and 65 wt.%from high carbon sludge.Notably,the zeolite crystallinity reported in this study was the higher than previous studies on this topic.The outlined approach may allow value adding of alum waste and produce a commodity which could be used locally by the water treatment plant as a water softener.展开更多
High phosphorus(P)saturation arising from historic P inputs to protected vegetable fields(PVFs)drives high P mobilisation to waterbodies.Amendment of soils with alum has shown potential in terms of fixing labile P and...High phosphorus(P)saturation arising from historic P inputs to protected vegetable fields(PVFs)drives high P mobilisation to waterbodies.Amendment of soils with alum has shown potential in terms of fixing labile P and protecting water quality.The present 15 month pot experiment investigated P stabilisation across single alum application(Alum-1 treatment,20 g alum/kg soil incorporated into soil before the maize was sown),alum split applications(Alum-4 treatment,5 g alum/kg soil incorporated into soil before each crop was sown i.e.4×5 g/kg)and soil only treatment(Control).Results showed that the Alum-1 treatment caused the strongest stabilisation of soil labile P after maize plant removal,whereas the P stabilisation effect was gradually weakened due to the transformation of soil non-labile P to labile P and the reduced active Al^(3+)in soil solution.For the Alum-4 treatment,soil labile P decreased gradually with each crop planting and was lower than the Alum-1 treatment at the end of the final crop removal,without any impairment on plant growth.The better P stabilisation at the end of Alum-4 treatment was closely correlated with a progressive supply of Al^(3+)and a gradual decrease of pH,which resulted in higher contents of poorlycrystalline Al,Fe and exchangeable Ca.These aspects were conducive to increasing the soil P stabilisation and phosphate sorption.In terms of management,growers in continuous cropping systems could utilise split alum applications as a strategy to alleviate P losses in high-P enriched calcareous soil.展开更多
The dissolution kinetics and mechanisms of reaction of Batagbon Kaolin in sulphuric and fluosilicic acids were studied. Leaching temperature, acid concentration, particle size, solid-to-liquid ratio, and stirring spee...The dissolution kinetics and mechanisms of reaction of Batagbon Kaolin in sulphuric and fluosilicic acids were studied. Leaching temperature, acid concentration, particle size, solid-to-liquid ratio, and stirring speed were selected as process parameters. It is observed that the dissolution rate increases with decreasing particle size and solid-to-liquid ratio, and increases with stirring speed, acid concentration, and leaching temperature. The experimental results indicate that the dissolution rate is of mixed control via hydrogen ion [H＋] action, with reaction order of 0.813 and the reaction kinetics can be expressed as gmt=[1-（1-x）l/3＋y/6[（l-x）l/3＋ 1-2（1-x）2/3]. The activation energy of the process is determined to be 21.6 k J/mol. The level of the product quality is also evaluated.展开更多
Alum sludge （AS） is a world-wide by-product generated in the drinking water treatment process when aluminum salts are used as coagulant. Its high AI content makes it a potential adsorbent for flouride removal from w...Alum sludge （AS） is a world-wide by-product generated in the drinking water treatment process when aluminum salts are used as coagulant. Its high AI content makes it a potential adsorbent for flouride removal from water. A high performance adsorbent was fabricated via heat treatment of AS and batch adsorption experiments were carried out to investigate its flouride adosroption performance. The results indicated that AS treated at 300℃ （AS300） for 1 h had the highest adsorption capacity for fluoride （52.9% fluoride removal）. The adsorption of fluoride by AS300 fitted better the Langmuir isotherm model than the Freundlich model. The maximum fluoride adsorption capacity of AS300 increased from 4.0 to 9.3 mg/g sludge when reaction temperature increased from 15 to 35 ℃. Thermodynamic parameters showed that the adsorption of fluoride by AS was spontaneous and endothermie. Hence higher temperature was favorable for fluoride adsorption. The adsorption process followed the pseudo-second-order equation. In addition, the fluoride adsorption on AS300 decreased from 4.3 to 2.5 mg/g sludge when the solution initial pH increased from 4.0 to 9.0, which meant that adsorption capacity was greatly dependent upon the initial pH of the solution. The results provide new insight into the resource utilization of AS for fluoride removal.展开更多
Two experiments were conducted to evaluate the effect of alum on ammonia emission,live performance,and health of broilers.In experiment 1,the effect of alum （0,2,and 4%） supplementation on the emission of ammonia wa...Two experiments were conducted to evaluate the effect of alum on ammonia emission,live performance,and health of broilers.In experiment 1,the effect of alum （0,2,and 4%） supplementation on the emission of ammonia was measured.The effects of alum-treated litter and stocking density （12,16,and 20 birds m-2） on the live performance and incidence of footpad and hock dermatitis were investigated in experiment 2.Alum supplementation in chicken excreta significantly decreased pH from 8.06 to 5.27 and 3.62 by 2 and 4% alum treatments,respectively.Ammonia emission rate was reduced 73.0 and 75.8% by 2 and 4% alum treatments,respectively.The suppressed litter urease activity was detected in 4% alum treatment.Alum-amended litter （1 kg m-2） decreased atmosphere ammonia concentrations by 30% in broiler house.Alum-amended litter maintained a lower pH until 35 d of age.Body weight （BW） gain was decreased by alum treatment in the period of 4-7 wk of age.Higher stocking density （20 birds m-2） increased BW gain in the first 3 wk of age but decreased BW gain during the period of 4-7 wk of age.Neither alum nor stocking density treatments had a significant effect on feed intake and feed efficiency.Alum-treated litter had no detrimental effect on the development of footpad and hock burns.In contrast,high stocking density （20 bird m-2） increased the incidence of footpad and hock lesion.The result suggests that the decreased litter pH and suppressed bacterial urease activity by alum treatment is responsible for the decreased ammonia emission.At high stocking density,the increased litter moisture content should be responsible,at least partially,for the development of footpad and hock lesions.展开更多
Alum （KAl（SOa）E.12H2O） is an inexpensive, efficient, non-toxic and mild catalyst for the one-pot synthesis of α-aminopho- sphonates. A three component reaction of an aldehyde/ketone, an amine and triethyl phosphi...Alum （KAl（SOa）E.12H2O） is an inexpensive, efficient, non-toxic and mild catalyst for the one-pot synthesis of α-aminopho- sphonates. A three component reaction of an aldehyde/ketone, an amine and triethyl phosphite was carried out under solvent-free conditions to afford the corresponding α-aminophosphonates in short reaction times and high yields with the green aspects by avoiding toxic catalysts and solvents. 2009 Murlidhar S. Shingare. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
Excess reactive phosphorus(PO4)in waterways can lead to eutrophication.A low-cost approach to reducing PO4 levels in surface water was evaluated using the alum-based water treatment residual(Al-WTR)or Al-WTR augmented...Excess reactive phosphorus(PO4)in waterways can lead to eutrophication.A low-cost approach to reducing PO4 levels in surface water was evaluated using the alum-based water treatment residual(Al-WTR)or Al-WTR augmented with powdered activated carbon(PAC-WTR).Batch adsorption-desorption and continuous flow column experiments were performed to assess the specific adsorption capacities under various concentration and flow conditions.Both Al-WTR and PAC-WTR exhibited the ability to adsorb PO4.The overall,cumulative sorbed amount after a 28-d desorption step for Al-WTR was 33.93 mg/kg,significantly greater than the PAC-WTR value of 24.95 mg/kg(p<0.05).The continuous flow column experiments showed a theoretical PO4 uptake of 9.00 mg/g for Al-WTR and 7.14 mg/g for PAC-WTR over 720 h.When surface water was used,the Al-WTR and PAC-WTR columns removed 67.4%and 62.1%of the PO4,respectively.These results indicated that Al-WTR was more effective for in-field evaluation.展开更多
Books and archives experience aging which is affected by a variety of factors, such as microorganism, humidity, light and components of paper . Thus, the studies concerning impacts of those factors on paper aging are ...Books and archives experience aging which is affected by a variety of factors, such as microorganism, humidity, light and components of paper . Thus, the studies concerning impacts of those factors on paper aging are required. In this paper, an accelerated paper aging was carried out to investigate the effects of acid and metals such as alum, copper (Ⅱ) sulfate, copper (Ⅱ) chloride, and iron (Ⅲ) chloride on paper aging. It was found that both acid and metals had impacts on paper aging. In particular, paper aging was far more accelerated in case that acid and metals were present in paper at the same time.展开更多
This work investigates coag-flocculation optimization treatment of alum-brewery effluent system via response surface methodology (RSM). To minimize suspended and dissolved particles (SDP), experiments were carried out...This work investigates coag-flocculation optimization treatment of alum-brewery effluent system via response surface methodology (RSM). To minimize suspended and dissolved particles (SDP), experiments were carried out using nephelometric jar test and 23-factorial design with three star-points, six-center-points and two replications. A central composite design, which is the standard design of RSM, was used to evaluate the effects and interactions of three major factors (coagulation pH, coagulant dosage, settling time) on the treatment efficiency. Multivariable quadratic model developed for the response studied indicates the optimum conditions to be 9, 500mg/l and 20minutes for coagulation pH, coagulant dosage and settling time, respectively. At optimum, the SDP was reduced from 10831.490mg/l to 801.451mg/l, representing 92.601% removal efficiency. RSM has demonstrated to be appropriate approach for the optimization of the coag-flocculation process by statistical evaluation.展开更多
The chemical coagulation-flocculation technology is touted as one of the valuable techniques and widely used for wastewater treatment because of its simplicity and effectiveness. So far, a number of flocculants have b...The chemical coagulation-flocculation technology is touted as one of the valuable techniques and widely used for wastewater treatment because of its simplicity and effectiveness. So far, a number of flocculants have been fabricated to ameliorate the flocculation process in water treatment such as alum, polyaluminium chloride. Despite its broad application in water treatment, accumulation of alum in sludge has been reported as the main source of a disposal problem. Furthermore, recent studies suggested that the presence of alum in sludge may lead to human health problems. Here in, we have used alkalization method to recover alum present in sludge collected from Kimisagara water treatment plant located in Kigali capital city of Rwanda. The recovered alum was used more than one time and showed excellent flocculation efficiency. Some physical parameters such as pH, Total Suspended Solids (TSS), Total Dissolved Solids (TDS), Conductivity and Turbidity were systematically tested and compared with those of World Health Organization (WHO) and Rwanda Standards Board (RSB) standards for drinking water. The results showed that alum present in sludge can be recovered and reused for multiple times.展开更多
This study was considered to assess the risk of alum which is used in Sudan for drinking water treatment purposes for a long period without toxicity freedom records .Newzealand rabbits were chosen for animal phase tri...This study was considered to assess the risk of alum which is used in Sudan for drinking water treatment purposes for a long period without toxicity freedom records .Newzealand rabbits were chosen for animal phase trials, divided into 3 groups. One group was the undosed controls. Test groups were given alum at dose rates of 1% and 20% respectively for two groups after an adaptation period. Clinical signs were observed together with postmortem and histopathological examinations. Chemical investigations included enzymatic, metabolic, electrolyte and hematological changes. The test rabbits demonstrated low voice, inappitence, whitish salivation, watery diarrhea and recumbence followed by emphysematous, lungs, electrolyte imbalance, renal dysfunctions, stiff focal inflammation of the empty intestines and congested liver with white spots. The control group was normal .On atomic absorption only the lungs kept residual alum, while the livers washed- out the substance ,may be via bile .Alum -dosed rabbits showed necrosis in the cortex and medulla of the kidney, emphysema in the lungs and necrosis in the hepatocytes. On evaluation of the above results, alum was considered to be toxic to Newzealand rabbits at dose rates tried.展开更多
基金The first author would like to appreciate Ministry of Higher Education, Missions Department, Egypt for the fi- nancial support granted through Channel Scheme Mission.
文摘The use of Fenton＇s reagent （Fe^2＋/H2O2） and Fenton-like reagents containing transition metals of Cu（Ⅱ）, Zn（Ⅱ）, Co（Ⅱ）, and Mn（Ⅱ） for an alum sludge conditioning to improve its dewaterability was investigated. The results obtained were compared with those obtained from conditioning the same alum sludge using cationic and anionic polymers. Experimental results show that Fenton＇s reagent was the best among the Fenton and Fenton-like reagents for the alum sludge conditioning. A considerable effectiveness of capillary suction time （CST） reduction efficiency of 47% can be achieved under test conditions of Fe^2＋/H2O2 = 20/125 mg/g DS （dry solid） and pH 6.0. The observation of floc-like particles after Fenton＇s reagent conditioning of alum sludge suggested that the mechanism of Fenton＇s reagent conditioning was different from that of polymer conditioning. In spite of the lower efficiency in the CST reduction of Fenton＇s reagent in alum sludge conditioning compared to that of polymer conditioning, Fenton＇s reagent offers a more environmentally safe option. Tiffs study provided an example of proactive treatment engineering, which is aimed at seeking a safe alternative to the use of polymers in sludge conditioning towards achieving a more sustainable sludge management strategy.
基金the Research and Development Fund of the Faculty of Engineering,Burapha University(No.70/2551)for financial supports
文摘A coagulation-flocculation process is typically employed to treat the industrial wastewater generated by the consumer products industry manufacturing detergents, soaps, and others. The expenditure of chemicals including coagulants and chemicals for pH adjustment is costly for treating this wastewater. The objective of this study was to evaluate the feasibility of reusing the aluminum sulfate （alum） sludge as a coagulant or as a coagulation aid so that the fresh alum dosage can be minimized or the removal efficiency can be enhanced. The experiments were conducted in a jar-test apparatus simulating the coagulation-flocculation process for simultaneous removals of organic matters, anionic surfactants, suspended solids, and turbidity. At the optimum initial pH value of 10 and the fresh alum concentration of 400 mg/L, the total suspended solids （TSS）, total chemical oxygen demand （TCOD）, total anionic surfactants, and turbidity removal efficiencies were 71.5%, 76.4%, 95.4%, and 98.2%, respectively. The addition of alum sludge as a coagulant alone without any fresh alum addition could significantly remove the turbidity, TCOD, and anionic surfactants. The TSS was left in the supernatants after the settling period, but would subsequently be removed by adding the fresh alum. The TSS, TCOD, and turbidity removal efficiencies were also enhanced when both the alum sludge and the fresh alum were employed. The TCOD removal efficiency over 80% has been accomplished, which has never fulfilled by using the fresh alum alone. It is concluded that the alum sludge could be reused for the treatment of industrial wastewater generated by the consumer products industry.
基金supported by the National Natural Science Foundation of China (No. 51278055,51179008)
文摘As safe byproducts of drinking water treatment processes,ferric and alum water treatment residuals（FARs） have the potential to be new phosphate（P） immobilization materials.In this study,batch experiments were conducted to investigate and compare the adsorption characteristics of three P species by FARs.The results showed that the kinetic processes of different P species＇ adsorption by FARs could be described by a pseudo second-order model.The ranking list of the initial adsorption rates with respect to different phosphates was pyrophosphate,phytate,orthophosphate,hexametaphosphate and glycerophosphate.Of the six models considered,the two-site Langmuir model most effectively described the adsorption characteristics of the various P species.Upon fitting the results,the maximum adsorption capacities were determined to be 40.24 mg/g for phytate,18.04 mg/g for pyrophosphate,17.14 mg/g for orthophosphate,15.86 mg/g for hexametaphosphate and 10.81 mg/g for glycerophosphate.In addition,the adsorption processes of the different P species were spontaneous endothermic processes and were favored at lower pH values.The pH dependency was found to be especially true for orthophosphate,where the adsorption capacity decreased by 1.22 mg/g with an increase in pH from 5 to 9.Fractionation of the adsorbed P species from the FARs demonstrated that Al-P and Fe-P were the dominating forms,constituting approximately 80%-90% of the total P fractions,which indicated that the adsorbed P species had a low leaching risk and could stably exist in the FARs.Therefore,the FARs could be effective in controlling pollution in water caused by different P species.
基金supported by the National Natural Science Foundation of China (No. 50778146)the Program for Changjiang Scholars and Innovative Research Teamin University (No. IRT0853)
文摘The effects of addition of calcium hydroxide on aluminum sulphate （or alum） coagulation for removal of natural organic matter （NOM） and its subsequent effect on the formation potentials of two major types of regulated disinfection byproducts （DBPs）, haloacetic acids （HAAs） and trihalomethanes （THMs）, have been examined. The results revealed several noteworthy phenomena. At the optimal coagulation pH （i.e. 6）, the coagulation behavior of NOM water solutions versus alum dose, showed large variation and a consequent great change in the formation potentials of the DBPs at certain coagulant doses. However, with addition of a relatively small amount of Ca（OH）2, although the zeta potential of coagulated floes remained almost the same, NOM removal became more consistent with alum dose. Importantly, also the detrimental effect of charge reversal on NOM removal at the low coagulant dose disappeared. This resulted in a steady decrease in the formation potentials of DBPs as a function of the coagulant dose. Moreover, the addition of Ca（OH）2 broadened the pH range of alum coagulation and promoted further reduction of the formation potentials of the DBPs. The enhancement effects of Ca（OH）2 assisted alum coagulation are especially pronounced at pH 7 and 8. Finally, synchronous fluorescence spectra showed that the reduction in DBPs formation potential by Ca（OH）2-assisted alum coagulation was connected to an enhanced removal of small hydrophobic and hydrophilic HA molecules. Ca（OH）2-assistance of alum coagulation appeared to increase substantially the removal of the hydrophilic HA fraction responsible for HAAs formation, prompting further reduction of HAA formation potentials.
文摘Ferrate is an excellent water treatment agent for its multi functions in oxidation, disinfection, coagulation and adsorption, but its coagulation ability depends on its dosage and is after its oxidation. This paper focuses on preparing a new kind of ferrate combined with alum to enhance its coagulation function for water purification. An effective electrolysis reactor was designed and employed in the test. Some key parameters in the process of electrolysis concerning the preparation efficiency, such as the current density, temperature and alkalinity were also investigated. The proper conditions for ferrate alum preparation were determined. Under the condition of 5V given voltage, 6h electrolyzing interval, below 2% alum concentration (in weight), a combined liquid ferrate alum products was successfully prepared, which contained 0.0294 mol/L FeO 2- 4 and 0.0302 mol/L total soluble ferron with 2% Al 2O 3. There was no insoluble ferron produced by controlling an optimum electrochemical condition.
文摘Generation of alum sludge(AS)at drinking water treatment plants represents an environmental liability and adds to the cost of water purification.Consequently,this study explored the feasibility of using low and high carbon containing alum sludge from two water treatment plants to synthesize zeolite LTA.The hypothesis was that zeolite LTA synthesis was dependant upon alum sludge source and that a range of strategies may be required to optimize zeolite crystallinity.Zeolite characteristics such as morphology,phase composition,crystallinity,and particle size distribution were recorded."One pot"hydrothermal synthesis of precursor gel with molar composition 4.2 Na2O:Al2O3:1.2 SiO_(2):168 H2O at 80℃ for 3 hr resulted in 25 and 46 wt.%zeolite LTA from high and low carbonaceous sludge,respectively.Prior to hydrothermal reaction stage it was discovered that ageing of the gel,addition of zeolite LTA seeds,ultrasonic treatment and calcination all promoted zeolite LTA formation.Calcination of the alum sludge at 700℃ for 2 hr before hydrothermal synthesis resulted in particle size reduction and the highest amount of crystalline zeolite LTA:79 wt.%from low carbon sludge and 65 wt.%from high carbon sludge.Notably,the zeolite crystallinity reported in this study was the higher than previous studies on this topic.The outlined approach may allow value adding of alum waste and produce a commodity which could be used locally by the water treatment plant as a water softener.
基金supported by the National Key Research and Development Program of China(No.2016YFD0801006)the China Agriculture Research System(No.CARS-23-B16)。
文摘High phosphorus(P)saturation arising from historic P inputs to protected vegetable fields(PVFs)drives high P mobilisation to waterbodies.Amendment of soils with alum has shown potential in terms of fixing labile P and protecting water quality.The present 15 month pot experiment investigated P stabilisation across single alum application(Alum-1 treatment,20 g alum/kg soil incorporated into soil before the maize was sown),alum split applications(Alum-4 treatment,5 g alum/kg soil incorporated into soil before each crop was sown i.e.4×5 g/kg)and soil only treatment(Control).Results showed that the Alum-1 treatment caused the strongest stabilisation of soil labile P after maize plant removal,whereas the P stabilisation effect was gradually weakened due to the transformation of soil non-labile P to labile P and the reduced active Al^(3+)in soil solution.For the Alum-4 treatment,soil labile P decreased gradually with each crop planting and was lower than the Alum-1 treatment at the end of the final crop removal,without any impairment on plant growth.The better P stabilisation at the end of Alum-4 treatment was closely correlated with a progressive supply of Al^(3+)and a gradual decrease of pH,which resulted in higher contents of poorlycrystalline Al,Fe and exchangeable Ca.These aspects were conducive to increasing the soil P stabilisation and phosphate sorption.In terms of management,growers in continuous cropping systems could utilise split alum applications as a strategy to alleviate P losses in high-P enriched calcareous soil.
文摘The dissolution kinetics and mechanisms of reaction of Batagbon Kaolin in sulphuric and fluosilicic acids were studied. Leaching temperature, acid concentration, particle size, solid-to-liquid ratio, and stirring speed were selected as process parameters. It is observed that the dissolution rate increases with decreasing particle size and solid-to-liquid ratio, and increases with stirring speed, acid concentration, and leaching temperature. The experimental results indicate that the dissolution rate is of mixed control via hydrogen ion [H＋] action, with reaction order of 0.813 and the reaction kinetics can be expressed as gmt=[1-（1-x）l/3＋y/6[（l-x）l/3＋ 1-2（1-x）2/3]. The activation energy of the process is determined to be 21.6 k J/mol. The level of the product quality is also evaluated.
基金Research Fund for Introduced High-Level Talents of North China University of Water Resources and Electric Power,ChinaResearch Fund for Key Scientific Project of Education Department of Henan Province,China(No.13B560114)Joint Research Fund for Overseas Chinese Scholars and Scholars in Hong Kong and Macao,China(No.51328803)
文摘Alum sludge （AS） is a world-wide by-product generated in the drinking water treatment process when aluminum salts are used as coagulant. Its high AI content makes it a potential adsorbent for flouride removal from water. A high performance adsorbent was fabricated via heat treatment of AS and batch adsorption experiments were carried out to investigate its flouride adosroption performance. The results indicated that AS treated at 300℃ （AS300） for 1 h had the highest adsorption capacity for fluoride （52.9% fluoride removal）. The adsorption of fluoride by AS300 fitted better the Langmuir isotherm model than the Freundlich model. The maximum fluoride adsorption capacity of AS300 increased from 4.0 to 9.3 mg/g sludge when reaction temperature increased from 15 to 35 ℃. Thermodynamic parameters showed that the adsorption of fluoride by AS was spontaneous and endothermie. Hence higher temperature was favorable for fluoride adsorption. The adsorption process followed the pseudo-second-order equation. In addition, the fluoride adsorption on AS300 decreased from 4.3 to 2.5 mg/g sludge when the solution initial pH increased from 4.0 to 9.0, which meant that adsorption capacity was greatly dependent upon the initial pH of the solution. The results provide new insight into the resource utilization of AS for fluoride removal.
基金supported by the National Natural Science Foundation of China (30771573)the Natural Science Fund for Distinguished Young Scholars of Shandong,China (2008JQB01001)
文摘Two experiments were conducted to evaluate the effect of alum on ammonia emission,live performance,and health of broilers.In experiment 1,the effect of alum （0,2,and 4%） supplementation on the emission of ammonia was measured.The effects of alum-treated litter and stocking density （12,16,and 20 birds m-2） on the live performance and incidence of footpad and hock dermatitis were investigated in experiment 2.Alum supplementation in chicken excreta significantly decreased pH from 8.06 to 5.27 and 3.62 by 2 and 4% alum treatments,respectively.Ammonia emission rate was reduced 73.0 and 75.8% by 2 and 4% alum treatments,respectively.The suppressed litter urease activity was detected in 4% alum treatment.Alum-amended litter （1 kg m-2） decreased atmosphere ammonia concentrations by 30% in broiler house.Alum-amended litter maintained a lower pH until 35 d of age.Body weight （BW） gain was decreased by alum treatment in the period of 4-7 wk of age.Higher stocking density （20 birds m-2） increased BW gain in the first 3 wk of age but decreased BW gain during the period of 4-7 wk of age.Neither alum nor stocking density treatments had a significant effect on feed intake and feed efficiency.Alum-treated litter had no detrimental effect on the development of footpad and hock burns.In contrast,high stocking density （20 bird m-2） increased the incidence of footpad and hock lesion.The result suggests that the decreased litter pH and suppressed bacterial urease activity by alum treatment is responsible for the decreased ammonia emission.At high stocking density,the increased litter moisture content should be responsible,at least partially,for the development of footpad and hock lesions.
文摘Alum （KAl（SOa）E.12H2O） is an inexpensive, efficient, non-toxic and mild catalyst for the one-pot synthesis of α-aminopho- sphonates. A three component reaction of an aldehyde/ketone, an amine and triethyl phosphite was carried out under solvent-free conditions to afford the corresponding α-aminophosphonates in short reaction times and high yields with the green aspects by avoiding toxic catalysts and solvents. 2009 Murlidhar S. Shingare. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
基金This work was supported by Ohio EPA 319(Grant No.17(H)EPA-17)and the Ohio Water Development Authority(Grant No.80-17).
文摘Excess reactive phosphorus(PO4)in waterways can lead to eutrophication.A low-cost approach to reducing PO4 levels in surface water was evaluated using the alum-based water treatment residual(Al-WTR)or Al-WTR augmented with powdered activated carbon(PAC-WTR).Batch adsorption-desorption and continuous flow column experiments were performed to assess the specific adsorption capacities under various concentration and flow conditions.Both Al-WTR and PAC-WTR exhibited the ability to adsorb PO4.The overall,cumulative sorbed amount after a 28-d desorption step for Al-WTR was 33.93 mg/kg,significantly greater than the PAC-WTR value of 24.95 mg/kg(p<0.05).The continuous flow column experiments showed a theoretical PO4 uptake of 9.00 mg/g for Al-WTR and 7.14 mg/g for PAC-WTR over 720 h.When surface water was used,the Al-WTR and PAC-WTR columns removed 67.4%and 62.1%of the PO4,respectively.These results indicated that Al-WTR was more effective for in-field evaluation.
文摘Books and archives experience aging which is affected by a variety of factors, such as microorganism, humidity, light and components of paper . Thus, the studies concerning impacts of those factors on paper aging are required. In this paper, an accelerated paper aging was carried out to investigate the effects of acid and metals such as alum, copper (Ⅱ) sulfate, copper (Ⅱ) chloride, and iron (Ⅲ) chloride on paper aging. It was found that both acid and metals had impacts on paper aging. In particular, paper aging was far more accelerated in case that acid and metals were present in paper at the same time.
文摘This work investigates coag-flocculation optimization treatment of alum-brewery effluent system via response surface methodology (RSM). To minimize suspended and dissolved particles (SDP), experiments were carried out using nephelometric jar test and 23-factorial design with three star-points, six-center-points and two replications. A central composite design, which is the standard design of RSM, was used to evaluate the effects and interactions of three major factors (coagulation pH, coagulant dosage, settling time) on the treatment efficiency. Multivariable quadratic model developed for the response studied indicates the optimum conditions to be 9, 500mg/l and 20minutes for coagulation pH, coagulant dosage and settling time, respectively. At optimum, the SDP was reduced from 10831.490mg/l to 801.451mg/l, representing 92.601% removal efficiency. RSM has demonstrated to be appropriate approach for the optimization of the coag-flocculation process by statistical evaluation.
文摘The chemical coagulation-flocculation technology is touted as one of the valuable techniques and widely used for wastewater treatment because of its simplicity and effectiveness. So far, a number of flocculants have been fabricated to ameliorate the flocculation process in water treatment such as alum, polyaluminium chloride. Despite its broad application in water treatment, accumulation of alum in sludge has been reported as the main source of a disposal problem. Furthermore, recent studies suggested that the presence of alum in sludge may lead to human health problems. Here in, we have used alkalization method to recover alum present in sludge collected from Kimisagara water treatment plant located in Kigali capital city of Rwanda. The recovered alum was used more than one time and showed excellent flocculation efficiency. Some physical parameters such as pH, Total Suspended Solids (TSS), Total Dissolved Solids (TDS), Conductivity and Turbidity were systematically tested and compared with those of World Health Organization (WHO) and Rwanda Standards Board (RSB) standards for drinking water. The results showed that alum present in sludge can be recovered and reused for multiple times.
文摘This study was considered to assess the risk of alum which is used in Sudan for drinking water treatment purposes for a long period without toxicity freedom records .Newzealand rabbits were chosen for animal phase trials, divided into 3 groups. One group was the undosed controls. Test groups were given alum at dose rates of 1% and 20% respectively for two groups after an adaptation period. Clinical signs were observed together with postmortem and histopathological examinations. Chemical investigations included enzymatic, metabolic, electrolyte and hematological changes. The test rabbits demonstrated low voice, inappitence, whitish salivation, watery diarrhea and recumbence followed by emphysematous, lungs, electrolyte imbalance, renal dysfunctions, stiff focal inflammation of the empty intestines and congested liver with white spots. The control group was normal .On atomic absorption only the lungs kept residual alum, while the livers washed- out the substance ,may be via bile .Alum -dosed rabbits showed necrosis in the cortex and medulla of the kidney, emphysema in the lungs and necrosis in the hepatocytes. On evaluation of the above results, alum was considered to be toxic to Newzealand rabbits at dose rates tried.
