The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform
Qiu Zhan - One of the best experts on this subject based on the ideXlab platform.
-
Conditioning for excess sludge and ozonized sludge by Ferric Salt and polyacrylamide: Orthogonal optimization, rheological characteristics and floc properties
Chemical Engineering Journal, 2019Co-Authors: Zhen Zhou, Liuyu Chen, Guang Chen, Yue Zhang, Lingyan Jiang, Qiu ZhanAbstract:Abstract Effects of molecular weight (MW), charge density (CD) and structure of polyacrylamide (PAM) on conditioning of excess sludge (ES) and ozonized sludge (OS) with/without Ferric Salt pretreatment (FSP) were investigated by orthogonal experiment. Rheological and morphological analyses were conducted to elucidate conditioning mechanism of ES and OS. OS had smaller particle size, worse filterability, lower flowability and more evident thixotropy than ES, and required FSP before conditioning. Orthogonal experiment showed that the optimal conditioner was PAM with medium MW and cross-linked structure for ES, and high MW and linear structure for OS after FSP, respectively. The specific resistance of filtration and capillary suction time were reduced to (1.2 ± 0.1) × 1012 m/kg and 25.8 ± 1.9 s for OS after FSP and optimized PAM conditioning, and particle size increased from 30.3 for OS to 269.7 μm after conditioning. The limiting viscosity, structural strength and thixotropy of conditioned OS were lower than conditioned ES, but greatly enhanced by FSP. Morphological analyses confirmed that ozonation cracked microbial cells of sludge, and FSP obtained more porous structure and reinforced floc strength of PAM conditioned OS.
Feng Xiao - One of the best experts on this subject based on the ideXlab platform.
-
Speciation characterization and coagulation of poly-silica-Ferric-chloride: the role of hydrolyzed Fe(III) and silica interaction.
Journal of environmental sciences (China), 2011Co-Authors: Jian Shi, Yan Zhang, Kaiyun Zou, Feng XiaoAbstract:Abstract The highly efficient inorganic polymer flocculants (IPFs) of the Ferric-silica system is a new and promising coagulant. Interactions between Ferric species and silica play a large part in the coagulation of suspensions. These effects are quite distinct from those associated with polymeric or colloid silica. However, although these species are key to coagulation efficiency, they have not been comprehensively discussed. A new type of coagulant, poly-silica-Ferric-chloride (PFSC), was synthesized by co-polymerization and characterized by time complexation spectroscopy and photon correlation spectroscopy. Compared with traditional Ferric Salt, the results indicated that PFSC had a higher molecular weight, lesser positive charge, lower Fe b and higher Fe c . The higher the Si/Fe ratio, the higher the silica and lower the silica found. The PFSC with appropriate polysilica acid not only obtained better coagulation/flocculation efficiency in turbidity removal, enhanced the flocculation index (FI) and provided less residual Ferric, it also lowered water treatment costs compared to traditional Ferric Salt. Results showed that PFSC could remove colloid particles in water by charge neutralization and sweeping, adsorption bridging mechanism.
Z. John Zhang - One of the best experts on this subject based on the ideXlab platform.
-
Synthesis of magnetic spinel ferrite CoFe2O4 nanoparticles from Ferric Salt and characterization of the size-dependent superparamagnetic properties
Pure and Applied Chemistry, 2000Co-Authors: Chao Liu, Adam J. Rondinone, Z. John ZhangAbstract:The CoFe2O4 nanoparticles have been synthesized by using a stable Ferric Salt of FeCl3 with a micellar microemulsion method. The normal micelles are formed by sodium dodecyl sulfate (NaDS) in aqueous solutions. The mean size of the nanoparticles can be controlled from less than 4 nm to about 10 nm through controlling the concentrations of the reagents. The neutron diffraction in combination with the Rietveld refinement shows that these CoFe2O4 nanoparticles have a high degree of inversion with 66% of the tetrahedral sublattice occupied by Fe3+. Magnetic measurements and neutron diffraction studies demonstrate the superparamagnetic nature of these CoFe2O4 nanoparticles. The size-dependent superparamagnetic properties of CoFe2O4 nanoparticles have also been systematically studied. The blocking temperature and coercive field of the nanoparticles increase with increasing size of the nanoparticles. The superparamagnetic behaviors of CoFe2O4 nanoparticles are consistent with the Stoner-Wohlfarth theory of single domain particles.
Zheng Ping - One of the best experts on this subject based on the ideXlab platform.
-
Comparison of Phosphorus Removal Processes by Ferrous Salts and Ferric Salts
Journal of Chemical Engineering of Chinese Universities, 2013Co-Authors: Zheng PingAbstract:Ferric Salts and ferrous Salts are common precipitators used for chemical phosphorus removal technology.In order to provide theoretical basis and suitable technical parameters for the selecting and optimizing the technic of phosphorus removal by iron Salts,theoretical analysis and practical experiments were conducted.Herein the phosphorus removal processes were compared in respect of thermodynamics,stoichiometry,process characteristics and operation cost.The results of theoretical analysis show that,compared to ferrous Salt,the reaction between Ferric Salt and phosphate is more favorable,the dose of precipitant required is less and the residual phosphorus concentration is lower.However,phosphorus removal with Ferric Salt leads to a low pH,which implies that more alkali for aftertreatment is needed to meet the discharge standard.The results of practical experiments show that,the effects of iron/phosphorus ratio and pH are significant on phosphorus removal for both Ferric Salt and ferrous Salt,but the combined effects of factors(Fe/P,pH,FMS – Flash Mixing Speed) are obviously different from one another.During the wastewater treatment,the synergic action of the above operation parameters should be fully used,while the antagonistic action of operation parameters should be carefully avoided.Compared with ferrous Salt,the phosphorus removal with Ferric Salt is more efficient with less precipitant requirement and lower residual phosphorus concentration,but higher cost.Based on the theoretical analysis and practical experiment,the mixture of Ferric Salt and ferrous Salt is recommended as an alternative precipitant,or ferrous Salt is suggested to be partially or completely oxidized into Ferric Salt for phosphorus removal,which could combine the advantages of both the two technologies.
-
process optimization for phosphorus removal with Ferric Salt by response surface methodology
Journal of Zhejiang University Agriculture and Life Sciences, 2012Co-Authors: Zhang Meng, Yu Xiaoqing, Qiu Lin, Lu Huifeng, Zheng PingAbstract:Currently eutrophication has become a hot issue all over the world.The removal of phosphorus from wastewaters is regarded as an important approach to fight eutrophication since phosphorus is one of the main factors causing eutrophication.The chemical phosphorus removal technology with Ferric Salt as a precipitant is in widespread use to meet the wastewater discharge standard.The optimization of phosphorus removal technology helps to cut down the cost of wastewater treatment.Herein the response surface methodology(RSM)is introduced to investigate the individual and combined effects of operation parameters.The performance of chemical phosphorus removal technology with Ferric Salt as a precipitant is dependant on a series of factors.Fe/P ratio,pH and flash mixing speed(FMS)were chosen as objects of study,and single-factor experiment and multiple-factor experiment were carried out to optimize the phosphorus removal efficiency.The results of single-factor experiment showed that both Fe/P ratio and pH had significant effects on phosphorus removal,but FMS did not.When the phosphorus concentration was 100mg/L,the optimal operation parameters were Fe/P ratio 3.0,pH 8.0,FMS 175-225r/min.The results of multiple-factor experiment showed that the individual effects of operation parameters on phosphorus removal were in order as Fe/PpH FMS.The combined effects of operation parameters were in order as Fe/P-FMS pH-FMS Fe/P-pH,among which the effects of Fe/P-FMS and Fe/P-pH were positive and the effect of pH-FMS was negative.Based on the experiment,"priority/combination"model was proposed to enhance the phosphorus removal with Ferric Salt as a precipitant.The optimal operation parameters were as follows:Fe/P=2.57,pH=6.31and FMS=136r/min,when the phosphorus concentration was 100mg/L.Both synthetic and real wastewaters were used to verify the feasibility of"priority/combination"model.Operated according to the model,the phosphorus removal was larger than 97%and the fractional error was less than 3%.It can be concluded that the response surface methodology is feasible for the optimization of operation parameters in wastewater treatment processes.The"priority/combination"model is effective for the improvement of phosphorus removal from wastewaters with Ferric Salt as a precipitant.During the wastewater treatment,the synergic action of operation parameters should be fully used,while the antagonistic action of operation parameters should be carefully avoided.
Zhen Zhou - One of the best experts on this subject based on the ideXlab platform.
-
Conditioning of raw sludge and thermally hydrolyzed sludge by Ferric Salt and cationic polyacrylamide: rheological analysis
Water Science and Technology, 2021Co-Authors: Liqiang Duan, Zhen Zhou, Xiaohu DaiAbstract:Abstract In this study, the conditioning effect of cationic polyacrylamide (CPAM) with different charge densities on raw sludge (RS) and thermo-hydrolyzed sludge (HS) pretreated with or without Ferric Salt is studied through orthogonal experiments. In addition, this paper uses the principles of rheology and morphology to analyze and clarify the conditioning mechanism of RS and HS, and reveals the mechanism of thermal hydrolysis to improve the dewatering performance of sludge. Compared with the RS, the HS has smaller particle size, better filterability, stronger fluidity and more obvious thixotropy. However, due to the influence of filter pressing time, Ferric Salt should be added before conditioning. The orthogonal experiment shows that the optimal conditioner is CPAM with charge density of 60, and the specific resistance to filtration and capillary suction time of the adjusted thermo-hydrolyzed sludge are reduced to (1.11 ± 0.07) × 1012 m/kg and 16.1 ± 1.8 s; the particle size increased from 61.2 to 253.5 μm. The moisture content of the sludge cake is about 48%. The structural strength and thixotropy of HS are higher than those of the RS, and can be greatly improved by adding Ferric Salt. Morphological analysis confirms that thermal hydrolysis can lyse microbial cells in sludge, and the sludge treated with Ferric Salt will have more porous structure and stronger flocculation strength.
-
Conditioning for excess sludge and ozonized sludge by Ferric Salt and polyacrylamide: Orthogonal optimization, rheological characteristics and floc properties
Chemical Engineering Journal, 2019Co-Authors: Zhen Zhou, Liuyu Chen, Guang Chen, Yue Zhang, Lingyan Jiang, Qiu ZhanAbstract:Abstract Effects of molecular weight (MW), charge density (CD) and structure of polyacrylamide (PAM) on conditioning of excess sludge (ES) and ozonized sludge (OS) with/without Ferric Salt pretreatment (FSP) were investigated by orthogonal experiment. Rheological and morphological analyses were conducted to elucidate conditioning mechanism of ES and OS. OS had smaller particle size, worse filterability, lower flowability and more evident thixotropy than ES, and required FSP before conditioning. Orthogonal experiment showed that the optimal conditioner was PAM with medium MW and cross-linked structure for ES, and high MW and linear structure for OS after FSP, respectively. The specific resistance of filtration and capillary suction time were reduced to (1.2 ± 0.1) × 1012 m/kg and 25.8 ± 1.9 s for OS after FSP and optimized PAM conditioning, and particle size increased from 30.3 for OS to 269.7 μm after conditioning. The limiting viscosity, structural strength and thixotropy of conditioned OS were lower than conditioned ES, but greatly enhanced by FSP. Morphological analyses confirmed that ozonation cracked microbial cells of sludge, and FSP obtained more porous structure and reinforced floc strength of PAM conditioned OS.