Polymeric Aluminum Ferric Chloride Research Articles

The application of chitosan quaternary ammonium salt to replace polymeric aluminum ferric chloride for sewage sludge dewatering

Inorganic coagulants such as poly aluminum ferric chloride (Al/Fe) are applied conventionally to sewage sludge dewatering and can be retained in the sludge cake, causing its conductivity to increase and generate secondary pollution. To reduce these disadvantages, there is a need to develop alternative, more sustainable chemicals as substitutes for conventional inorganic coagulants. In the present investigation, the application of a polymeric chitosan quaternary ammonium salt (CQAS) is explored as a complete, or partial, replacement for Al/Fe in the context of sludge dewatering processes. Laboratory experiments using digested sewage sludge showed that CQAS could effectively substitute for over 80 % of the Al/Fe inorganic coagulant in the sludge dewatering process. This substitution resulted in a reduction of sludge cake conductivity by more than 50 %. Simulation of sludge dewatering curves and imaging of the sludge surface indicated that the addition of CQAS led to an increase in nanosized pores, and a decrease in the specific resistance of the sludge filter cake as the dosage of Al/Fe decreased to around 30 %. The variations of fluorescence emission, quantum yield and carboxylic and amino groups, suggested that the chelating of Al/Fe decreased due to the bridging effects of CQAS. The CQAS had different flocculation bridging effects on various EPS fractions, which varied the amount of protein chelated with Al/Fe in each fraction. This study provides new information about the benefits of replacing conventional inorganic coagulants with natural organic polymers for sewage sludge dewatering, in terms of reduced sludge cake conductivity and greater dry solids content.

To treat wastewater with wastes: a highly efficient flocculant from fly ash and rice straw.

Water resources are vital for sustainable human life and economic activities. However, the issue of water pollution has reached alarming levels. Coking wastewater, known for its high concentrations of organic matter and toxic substances, poses significant environmental hazards. In response to this challenge, we developed a novel composite flocculant called polymeric aluminum ferric chloride (PAFC)/rice straw (PAFC/RS) from fly ash (a coal waste) and rice straw (an agricultural waste). The PAFC/RS was characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and Fourier transformed infrared (FT-IR). The flocculation performance of PAFC/RS was studied utilizing humic acid simulated coking wastewater as the target by measuring the chemical oxygen demand (COD), UV254, and turbidity. A removal efficiency of 97.3% for turbidity, 79.7% for COD, and 98.2% for UV254 was reached for the PAFC/RS with an optimal composition. It demonstrated a better flocculation effect compared to the traditional aluminum-iron-based inorganic flocculant. The PAFC/RS possesses great potential for a straightforward, cost-effective, and environmentally friendly water treatment material.

High-efficiency leaching of Al and Fe from fly ash for preparation of polymeric aluminum ferric chloride sulfate coagulant for wastewater treatment

Preparation of inorganic polymer coagulants from circulating fluidized bed (CFB) fly ash is one of the most significant value-added and environment-friendly approaches. Nevertheless, CFB fly ash presents relatively low solubility in acidic systems, which limits its utilization efficiency. In this paper, enhanced metal leaching from CFB fly ash using combined HCl-H2SO4 leaching process for polymeric aluminum ferric chloride sulfate (PAFCS) preparation was proposed. PAFCS with the different molar ratios of Al3+/SO42− and Al3+/Fe3+ were prepared from as-obtained leaching liquors and characterized by SEM, XRD, FTIR, and coagulation experiments. The leaching efficiencies of Al and Fe in CFB fly ash were up to 96.75% and 97.64% by combined HCl-H2SO4 leaching process. The optimal molar ratios of Al3+/SO42− and Al3+/Fe3+ for the turbidity and UV254 removal were 10:1 and 10:1, respectively, due to the three-dimensional chain-net structure and the highest [Al + Fe]b content. When applied to biochemical effluent of coking wastewater treatment, PAFCS exhibited excellent removal performance on both humic acid-like and fulvic acid-like matters. The resultant flocs of PAFCS presented the largest recovery factor (Rf = 0.37) and strength factor (Sf = 0.79) in contrast with PAC and PAFC. This work provides a novel and high-efficient Al and Fe leaching strategy from CFB fly ash to prepare Al-Fe coagulant.

Effects of coagulants on the catalytic properties of iron–manganese co-oxide filter films for ammonium and manganese removal from surface water

Abstract The removal of ammonium (NH4+) and manganese (Mn2+) is an important issue when treating surface water for drinking. A pilot-scale experiment was carried out with two parallel filter columns (filters R1 and R2) to compare the effects of three different coagulants (ferric chloride (FeCl3), polymerization ferric chloride (PFC), and polymeric aluminum ferric chloride (PAFC)) on the catalytic oxidation of an iron–manganese (Fe–Mn) co-oxide filter film for NH4+ and Mn2+ removal from surface water. In the results, FeCl3 was not conducive to the removal of NH4+ and Mn2+, probably because of the decrease in pH after its hydrolysis. PFC had a negligible effect on the catalytic activity of the Fe–Mn co-oxide for NH4+ and Mn2+ removal. With PAFC, the NH4+ removal efficiency of filter R2 began to decrease after 50 days, but the catalytic activity of the Fe–Mn co-oxide for Mn2+ removal remained unchanged. In order to explore the influence mechanisms of different coagulants, numerous analytical techniques were used to characterize the physicochemical properties of the Fe–Mn co-oxide samples. The results indicated that the difference in bonding interactions between aluminum (Al) and the Fe–Mn co-oxide with different running times may have caused the difference in activity. The bonded Al fraction was found to be tough to remove by backwashing in filter R2 with PAFC. The change in state of Al bonded to the surface might have been the fundamental cause of the decreased catalytic activity of the Fe–Mn co-oxide. Based on its removal performance over time, PFC coagulant can effectively ensure the continuous catalytic removal of NH4+ and Mn2+ from surface water with the Fe–Mn co-oxide filter.

Research on treating algae-polluted reservoir water by the process of pre-oxidation/dissolved air flotation/carbon sand filter

Abstract As the water diversion reservoir showed high organic matter and high algae in summer, the potassium permanganate pre-oxidation/dissolved air flotation/carbon sand double filter process was developed. The test results show that the optimum operation conditions of the combined process were as follows: the dosage of KMnO4 was 0.3 mg/L, the dosage of polymeric aluminum ferric chloride (PAFC) was 3.0 mg/L (Al3+), the reflux ratio was 10%, and the dissolved gas pressure was 0.3 Mpa. Taking Ji'nan Queshan reservoir water algae pollution as the research object, the average removal rate of chlorophyll a, blue-green algae, turbidity, particle number and total organic carbon (TOC) reached 66.64%, 95.44%, 94.45%, 99.34% and 46.68%, respectively; the methylisoborneol (MIB) removal rate was 92.47%, the odor level decreased with process flow from raw water level 4 to effluent level 1.5, geosmin (GSM) dropped below the detection limit, and the total removal rate of trihalomethane formation potential (THMFP) was 33.56%. The effluent of the combined process meets the requirements of the Hygienic Standard for Drinking Water (GB5749-2006) after it is disinfected.

Insight into removal of dissolved organic matter in post pharmaceutical wastewater by coagulation-UV/H2O2.

The removal of four dissolved organic matter (DOM) fractions, non-acid hydrophobics, hydrophobic acids, hydrophilics and transphilics, was achieved by coagulation-UV/H2O2 oxidation in post-pharmaceutical wastewater (PhWW). Coagulation with Polyferric chloride (PFC), Polymeric ferric sulfate (PFS) and Polymeric aluminum ferric chloride (PAFC) was studied separately to evaluate the effects of the initial pH and coagulant dosage. The coagulation-UV/H2O2 oxidation method resulted in much higher reduction rates for dissolved organic carbon (DOC) (by 75%) and UV254 (by 92%) than coagulation or UV/H2O2 oxidation alone. The proportion of non-acid hydrophobics, hydrophobic acids, transphilics and hydrophilics removed by coagulation was 54%, 49%, 27% and 12 %, while the combined treatment removed 92%, 87%, 70% and 39%, respectively. Parallel factor analysis (PARAFAC) of fluorescence measurements revealed that the humic-like fluorescent component C4 showed the highest removal (by 44%) during the coagulation stage. After coagulation-UV/H2O2 treatment, the humic-like fluorescent component C3 had the highest removal (by 72%), whereas xenobiotic organic fluorescent components C1 and C4 remained recalcitrant to decomposition. Significant correlations (R2 > 0.8) between C1 and the hydrophobic acids and non-acid hydrophobics suggested the possibility of using fluorescence spectroscopy as an effective tool to assess variations in DOM fraction treatment efficacy in coagulation-UV/H2O2 systems. After the combined treatment, toxic inhibition of cellular activity by post PhWW decreased from 88% to 47% and biodegradability increased from 0.1 to 0.52.

Preparation and coagulation performance of hybrid coagulant polyacrylamide–polymeric aluminum ferric chloride

ABSTRACTIn this study, we synthesized a novel hybrid coagulant, polyacrylamide (PAM)–polymeric aluminum ferric chloride (PAFC), by the polymerization of acrylamide monomer with the redox system (NH4)2S2O8–NaHSO3. The factors affecting the PAM–PAFC hybrid coagulant were investigated in an orthogonal experiment. The maximum intrinsic viscosity was observed at an initiator mass fraction of 0.5%, a polymerization temperature of 50 °C, a monomer mass fraction of 20%, and a polymerization time of 4 h, which were the optimum synthesis parameters. The spatial network structure of the PAM–PAFC hybrid coagulant was graphically determined by scanning electron microscopy. Hybrid PAM–PAFC was adopted to treat the kaolin–humic acid suspension and the synthetic dye wastewater. The effect of the coagulant dosage and pH on the coagulant experiments were examined. The coagulant experiment on the kaolin–humic acid suspension showed that the optimum treatment efficiency was achieved at a coagulants dosage of 0.6 mg/L, at which level the turbidity reductions with the inorganic PAFC coagulant, PAM–PAFC composite, and PAM–PAFC hybrid were 95.30%, 95.84%, and 98.38%, respectively. Treatment with the PAM–PAFC hybrid coagulant was also effective in removing Congo Red and Direct Fast Turquoise Blue GL; the color‐removal efficiencies for these dyes were higher than 93% and 94%, respectively. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46355.

Aluminum and iron leaching from power plant coal fly ash for preparation of polymeric aluminum ferric chloride

ABSTRACTIn this work, aluminum and iron existing in coal fly ash were extracted by the method of hydrochloric acid leaching. Effects of solid–liquid ratio, reaction temperature, reaction time, acid concentration, and raw ash mesh on recovery efficiencies of Al2O3 and Fe2O3 were investigated. X-ray diffraction analysis indicated that anhydrite, hematite, mullite and quartz were the dominant minerals in the raw fly ash sample. X-ray fluorescence technique was applied to determine the mass fractions of chemical components in the raw ash and leached residues, while the concentrations of Al2O3 and Fe2O3 in leaching solutions were measured by titration method. The optimal recovery efficiencies of Al2O3 and Fe2O3, obtained under the reaction condition of 95°C, 5 h, acid concentration of 20 wt.%, a solid–liquid ratio of 1:3.5 and raw ash mesh of 400, were 42.75% and 35.10%, respectively. After removing the leached residues, the leaching solutions were employed to manufacture flocculants of polymeric aluminum ferric chloride for treating the oil recovery wastewater from polymer flooding, which possessed high contents of suspended solids (SS) and oils. Microfiltration membrane and ultraviolet spectrophotometer were utilized to determine the contents of SS and oils in water samples. Through adjusting Al/Fe molar ratio to 20:1 and basicity to 70%, the maximum removing efficiencies of SS and oils can be achieved, respectively 96.1% and 91.5%. Moreover, increasing the iron content and basicity of flocculants within certain ranges contributed to improving the settling characteristic of flocs.

16S rRNA Gene Amplicon Sequencing Reveals Significant Changes in Microbial Compositions during Cyanobacteria-Laden Drinking Water Sludge Storage.

This is the first study to systematically investigate the microbial community structure in cyanobacteria-laden drinking water sludge generated by different types of coagulants (including AlCl3, FeCl3, and polymeric aluminum ferric chloride (PAFC)) using Illumina 16S rRNA gene MiSeq sequencing. Results show that Cyanobacteria, Proteobacteria, Firmicutes, Bacteroidetes, Verrucomicrobia, and Planctomycetes were the most dominant phyla in sludge, and because of the toxicity of high Al and Fe level in AlCl3 and FeCl3 sludges, respectively, the PAFC sludge exhibited greater microbial richness than that in AlCl3 and FeCl3 sludges. Due to lack of light and oxygen in sludge, relative abundance of the dominant genera Microcystis, Rhodobacter, Phenylobacterium, and Hydrogenophaga clearly decreased, especially after 4 days storage, and the amounts of extracellular microcystin and organic matter rose. As a result, the relative abundance of microcystin and organic degradation bacteria increased significantly, including pathogens such as Bacillus cereus, in particular after 4 days storage. Hence, sludge should be disposed of within 4 days to prevent massive growth of pathogens. In addition, because the increase of extracellular microcystins, organic matter, and pathogens in AlCl3 sludge was higher than that in FeCl3 and PAFC sludges, FeCl3 and PAFC may be ideal coagulants in drinking water treatment plants.

Optimization of and mechanism for the coagulation–flocculation of oil-field wastewater from polymer flooding

Oil-field wastewater from polymer flooding (OWPF) is difficult to deal with because it contains a high concentration of partially hydrolyzed polyacrylamide (HPAM), which stabilizes the wastewater. Coagulation–flocculation with polyepicholorohydrin–dimethylamine (EPI-DMA) and polymeric aluminum ferric chloride (PAFC) was used to optimize the treatment of OWPF. HPAM and COD removal were optimized using the response surface method (RSM), based on the Box–Behnken design (BBD). The variables EPI-DMA dose, PAFC dose, and pH were selected as the factors in the RSM to investigate their individual and interaction effects on the response values, HPAM and COD removal efficiencies. The results showed that HPAM and COD removal efficiencies of 95.4 and 85.7%, respectively, could be reached using 0.65 mg/L EPI-DMA, 924 mg/L PAFC, and pH 5.51. Fourier transform infrared spectroscopy, zeta potential, particle size analysis, scanning electron microscopy, and energy dispersive spectroscopy were used to study the mechanism of the coagulation–flocculation process. The results indicated that the main functions of the EPI-DMA and PAFC in the coagulation–flocculation process were electric neutralization, adsorption, and sweeping.

Preparation of polymeric aluminum ferric chloride (PAFC) coagulant from fly ash for the treatment of coal-washing wastewater

Fly ash-based polymeric aluminum ferric chloride (PAFC) was prepared from fly ash leached with acid; the PAFC was used as a coagulant to treat coal-washing wastewater. The effects of pH, reaction temperature, and reaction time on coagulant performance were investigated, with optimal conditions determined using response surface methodology. The coagulation mechanism of PAFC was explored by comparing its performance with commercially available polyaluminum chloride (PAC), using scanning electron microscopy and infrared spectroscopy analyses. Results showed that the optimum PAFC preparation conditions were at a pH of 3.60, a reaction temperature of 92°C, and a reaction time of 2.30 h. Under these conditions, the removal of suspended solids and chemical oxygen demand in treated coal-washing wastewater reached efficiencies of over 81 and 70%, respectively. This means that the prepared PAFC is an effective coal-washing wastewater treatment technique, combining the advantages of polyaluminum and polyferric coagulants.

Study on structural characterization and algae-removing efficiency of polymeric aluminum ferric sulfate (PAFS)

Polymeric aluminum ferric sulfate (PAFS), as a novel inorganic coagulant, was prepared through direct oxidation process using industrial by-product ferrous sulfate heptahydrate (FeSO4·7H2O) and industrial aluminum oxide (Al2O3 content of 16%) as the main materials. PAFS was characterized by Fourier transformed infrared spectrophotometer, scanning electron microscopy, and X-ray diffraction. The coagulation mechanism and molecular conformation of PAFS were analyzed and the different conditions of flocculation effect were investigated in the paper. In order to test the coagulating performances of PAFS, traditional coagulants such as polymeric ferric sulfate, polymeric aluminum chloride, and polymeric aluminum ferric chloride were used to carry out the comparison tests on algae removal efficiency. The results show the removal efficiency for turbidity and chlorophyll a using PAFS were 92.8 and 95.3%, respectively, which were higher than those of the traditional coagulants.

Color Removal from Dyeing Wastewater by the Polymer of Epichlorohydrin-Ethylenediamine

A new polymer of epichlorohydrin-ethylenediamine was obtained by suspension polycondensation of ethylenediamine with epichlorohydrin. The color removal performance and mechanism of the polymer in the treatment of synthetic reactive dyes wastewater was investigated, and in comparison with polymeric aluminum ferric chloride (PAFC) and polydimethyldiallylammonium chloride (PDMDAAC). The results showed that epichlorohydrin-ethylenediamine achieved higher color removal efficiency, and its adsorption-bridging and electric neutralization ability playedimportant roles in the flocculation process.

Dewatering Excess Sludges of Sanitary Sewage by Supersound and PAFC

This experiment adopted supersound and polymeric aluminum ferric chloride (PAFC) dewatering excess sludges. Firstly, aluminum chloride and ferric chloride were synthetized to a novel inorganic flocculant ——PAFC and the optimal molar ratio of A1 and Fe was 7:3. Secondly, PAFC singly dewatered excess sludges. The optimum technological conditionwas the optimum dosage of 120mg/L and pH of 8. As a result , the sludge water content decreased from 87.48% to 70.87%. Thirdly, supersound singly dewatered excess sludges. The optimum technological condition was the optimum power of 150W and time of 2.5min. Lastly, the combination of supersound and PAFC sludge dewatered excess sludges and moisture content was reduced to 70.01%.

Research on Treatment Process for Chemical Agent VX Polluted Water by Enhanced Coagulation

The influences of coagulant species, dose, water turbidity, and pollution situation of raw water on the results of enhanced coagulation have been investigated targeted at water contaminated by chemical agent. Ferric trichloride and polymeric aluminum ferric chloride (PAFC) acted as coagulant, poly dimethyl diallyl ammonium chloride (HCA) worked as coagulant aid and paraoxon acted as simulation agent of chemical agent VX in this process. The results show that: enhanced coagulation process cannot remove effectively chemical agent (paraoxon) in raw water; the result of treatment by PAFC and PAFC+HCA is better than that by FeCl3 and FeCl3+HCA; the addition of certain amount of HCA based on the condition that coagulant has been added will improve removal rate of both chemical agent and turbidity; the bigger the turbidity of raw water is, the higher the removal rate of paraoxon will be.

Micro-Flocculation - Film Processing Technology in Dealing with Beer Sterilized Wastewater

In order to improve beer sterilization effect of wastewater treatment, reduce the heat load of the sterilization wastewater on subsequent water treatment processes. In this paper, through optimizing transformation developed micro-flocculation -membrane treatment processes. Screening for the identification of inorganic polymeric aluminum ferric chloride flocculants as the technology. The best dosage was 15mg / L, the field test to verify the craft beer sterilized wastewater treatment effect. The results show that, micro flocculation membrane treatment process in the water after treatment of COD and turbidity removal rate is respectively 76% and 98%. To illustrate the use of this technology in the treatment of beer sterilizing water without two stage filtration, can effectively recycling sterilized wastewater.

Optimization of coagulant for raw water in Ganjiang River in winter

The paper aims to determine the optimal coagulant for raw water in the Ganjiang River during the winter. To explore their removal effect on turbidity and organic matters, respectively, by using FeCl3, Al2 (SO4)3, polyaluminum chloride, and polymeric aluminum ferric chloride as coagulant, there has been a total of six-jar test conducted. It was discovered that the removal rates of turbidity and organic maters vary a lot according to different raw water quality.

The Coagulation Performance and Floc Characteristics of Yellow River Reservoir Water Coagulated by Composite Coagulant Prepared by Polymeric Aluminum Ferric Chloride and Polydimethyl Diallylammonium Chloride

In this paper, inorganic polymeric ferric aluminum chloride (PFAC) and composite polymeric aluminum ferric chloride polydimethyl diallylammonium chloride (PFAC-PDADMAC) were applied for the coagulation treatment of Yellow River reservoir water. The coagulation efficiency of PFAC-PDADMAC for reservoir water treatment was investigated at different weight ratios (Ferric and Aluminum to PDADMAC, Wr=2, 4 and 8). During coagulation, the size distribution, breakage factor (Bf) and recovery factor (Rf) of flocs was investigated to systemically estimate the floc characteristics of PFAC-PDADMAC coagulation system. It was confirmed that coagulation performance of PFAC-PDADMAC was better than that of PFAC when Wr and dosage were 4 and 8 mg/L, respectively for Yellow River reservoir water coagulation. Although they were more sensitive to external interference, the flocs formed by PFAC-PDADMAC coagulation system had bigger size, faster growth rate and stronger re-growth capability than that by PFAC coagulation system. At Wr=4, the floc size and growth rate of flocs by PFAC-PDMDAAC coagulation were 409μm and 54 μm/min, respectively.

Depth filtration using novel fiber-ball filter media for the treatment of high-turbidity surface water

Performance of the novel fiber-ball filter was investigated for the treatment of high-turbidity surface water. Impact of different operating parameters, such as coagulant type, coagulant dose and filtration velocity on the effluent turbidity, dissolved organic carbon (DOC) and head loss, as well as the particle removal characteristics were studied. The clean-bed filtration results showed that the fiber-ball filters had a great potential for the removal of turbidity matters. Addition of polymeric aluminum ferric chloride (PAFC) enhanced the removal of effluent turbidity and DOC, while the head loss was also increased. The effluent turbidity could be <0.5NTU and the removal efficiency of DOC was ∼16% when the PAFC was dosed at 12mg/L. The effluent turbidity and DOC increased slightly with increasing filtration velocities (30–50m/h) due to the greater drag forces resulted from higher filtration velocities. However, the head loss was also increased. The particle removal characteristics indicated that large particles were primarily removed in the top 30cm of the filter bed and the deep depth in the bottom 20cm played an important role in preventing the occurrence of turbidity breakthrough. It was also found that particles in the size larger than 2μm could be well removed by the fiber-ball filters, implying the potential application for the removal of protozoa like Cryptosporidium (3–15μm) to meet the desired requirement for drinking water treatment during depth filtration.