Composite Coagulant Research Articles

A retrospective cohort study on the association between early coagulation disorder and short-term all-cause mortality of critically ill patients with congestive heart failure.

PurposeCoagulation disorder in congestive heart failure (CHF) has been well-documented. The prognostic value of a composite coagulation disorder score, which combines the absolute platelet count, international normalized ratio (INR), and activated partial thromboplastin time (APTT), has not been assessed in CHF. The present study endeavored to explore the association between the coagulation disorder score and adverse outcomes of critically ill patients with CHF.MethodsPatients diagnosed with CHF in the Medical Information Mart for Intensive Care III (MIMIC-III) database were included in the present retrospective cohort study. The coagulation disorder score was calculated according to the abnormalities of the absolute platelet count, INR, and APTT within 24 h after intensive care unit admission. The primary outcomes were the short-term all-cause mortality, including 30-, 90-day and in-hospital mortalities. The Kaplan–Meier (K-M) survival curve and the Cox proportional hazard model were performed to assess the correlation between coagulation disorder score and outcome events.ResultsA total of 6,895 patients were enrolled in this study and divided into four groups according to the coagulation disorder score. K-M survival curve preliminarily indicated that subjects with higher coagulation disorder score presented lower survival rate and shorter survival time. After adjustment for potential confounders, the multivariate Cox analysis further illustrated that elevated coagulation disorder score as a quartile variable was significantly associated with increased all-cause mortality (quartile 4 vs. quartile 1, 30-day: HR [95% CI], 1.98 [1.50, 2.62], 90-day: HR [95% CI], 1.88 [1.49, 2.37], in-hospital: HR [95%CI], 1.93 [1.42, 2.61]).ConclusionIn critically ill patients with CHF, ones with high coagulation disorder score tend to be worse clinical prognosis, which would be a promising biomarker and helpful for the management of CHF patients.

Performance improvement and mechanism of composite PAC/PDMDAAC coagulant via enhanced coagulation coupled with rapid sand filtration in the treatment of micro-polluted surface water

The coagulation and filtration are widely used for surface water due to cost effectiveness therefore the need to study its’ improvements for safe drinking water that meet national standards. The performance of enhanced coagulation of composite coagulants (ECC) using poly aluminium chloride/poly di-methyl di-allyl ammonium chloride (PAC/PDMDAAC) coupled with rapid sand filtration (RSF) was studied. This was performed using jar testing, optimized, and operated at same dosage and supernatant turbidity (SDST) mode; also, the interception points for PAC and composites at baseline turbidity between 1.0 and 1.50 NTU with fixed RSF operating conditions while water parameters like turbidity, CODMn, NH3N, and zeta potentials were used as indicators for improved removal rates. Furthermore, the floc size and morphology analysis at optimum dosage combined with zeta potentials were used to explained the mechanism of ECC-RSF. The results showed that most composites out-performed PAC only, before and at the interception points; however, beyond this point, the superior performance disappears with the increasing PAC dosage above 3.0 mg/L. At the optimum dosage, composite PAC/PDMDAAC at 1.60 dL/g, 10:1 showed the best overall removal rate at SDST mode of 99.36%, 64.50%, and 66.18%, respectively for turbidity, NH3N, and CODMn. The dominant mechanism of composite coagulation is charge neutralization within the dosage range used and strengthened by adsorption-bridging due to the presence of PDMDAAC while the major mechanism during filtration is adsorption. It was concluded that depending on the raw water quality, the coagulation mode of SDST at baseline turbidity near 1.0 NTU can maximized the water quality removal for composite PAC/PDMDAAC. New operational insights about maximizing the performance of composite PAC/PDMDAAC coagulants have been put forward.

Highly efficient Al-Ti gel as a coagulant for surface water treatment: Insights into the hydrolysate transformation and coagulation mechanism

In view of the insufficient coagulation efficiency of traditional inorganic coagulants, a series of Al-Ti gels with different Ti/triethanolamine (TEA), Ti/H2O, and Ti/Al molar ratios were prepared by sol-gel process in this study. Fourier transform infrared (FTIR) spectra of the Al-Ti gels preliminarily confirmed the interaction between Al and Ti by detecting the appearance of the Al-O-Ti bond. The peak shift of the chemical bonds in X-ray photoelectron spectra (XPS) and the transformation of the hydrolysate species in the Al-Ti gels were analyzed to further explore the interaction mechanism between Al and Ti. It was found that moderate TEA could inhibit the hydrolysis of Ti precursors by taking up the coordination sites of H2O to form a CO-Ti bond. Density functional theory (DFT) calculation results showed that Ti could be incorporated into the framework of aluminum hydrolysates to form an Al-O-Ti bond, and [Al2Ti2(OH)x(TEA)y(H2O)8-x-y]14-x was the most possible copolymerization hydrolysate. Based on the above research results, the most efficient Al-Ti gel was selected and applied to the actual lake water treatment. The highest UV254 removal efficiency with the addition of Al-Ti gel was > 60%, nearly 25% higher than that of Ti gel. The hydrolysates of Al-Ti gel, such as TiO(OH)2(am), Al(OH)3(am), and [Al2Ti2(OH)x(TEA)y(H2O)8-x-y]14-x, could remove organic matters through the incorporation of charge neutralization, adsorption, complexation, and sweeping effects. These results provide a new idea for studying the interaction mechanism between Al and Ti in composite coagulants, and have theoretical guiding significance to actual water treatment.

Zero residual heavy metals in aqueous media using composite coagulant converted from bauxite residue

Zero residual heavy metals in aqueous media using composite coagulant converted from bauxite residue

Coagulation behavior of polyaluminum-titanium chloride composite coagulant with humic acid: A mechanism analysis

The hydrolysate species of metal-based coagulants and the binding sites of humic acid (HA) are highly dependent on the pH conditions. Exploring the binding sites and modes between coagulant hydrolysates and HA molecules is critical to understanding the coagulation mechanism. In this paper, the binding behavior between HA molecules and the hydrolysates of a polyaluminum-titanium chloride composite coagulant (PATC) was investigated under different pH conditions by semi-quantitative FTIR and XPS. It was found that oligomeric and mesopolymeric hydrolysates were the dominant species under acid conditions, which could complex with the hydroxyl and carboxyl groups of HA by forming COAl/Ti coordinate bonds. However, large amounts of H+ could compete with Al3+ and weaken the removal efficiency of HA. With the increase of pH, the hydrolysis process of the PATC and the deprotonation of HA were simultaneously underway. Under weakly acid conditions, the complexation of the aluminum hydrolysates with carboxyl groups was improved due to the gradually diminishing competition of H+ and the enhanced charge neutralization of the further polymerized hydrolysates. Consequently, the maximum UV254 removal by adding PATC was observed at pH 6. Under alkaline conditions, the sweeping effect of amorphous hydroxide dominated the HA removals, which was accompanied by the surface complexation of Al/Ti nuclear with carboxyl groups as well as the hydrogen bonds between hydroxyl and hydroxide. This study provides a new clue for the interaction mechanisms between the hydrolysates of composite coagulants and the dominant functional groups of HA at various pH conditions.

A Review: Study of Surface Water and Its Treat-ment Using Biocoagulants

Abstract: Natural materials should be used in the coagulant-flocculation process as much as possible. According to the literature, it is worthwhile to develop and, if possible, convert natural materials into commercial. On the other hand, natural coagulants are insufficient as a primary treatment since their efficacy is being hampered by increasing restrictions. Emerging technology and in-depth research contribute to the creation of these restricted settings as well as the success of chemicals. Natural coagulants are also commonly employed as coagulant aids in conjunction with manufactured coagulants. The type of coagulants used in the treatment of waste-water coagulation, in particular the usage of natural coagulants, is the subject of this investigation. Natural materials' potential for future expansion as aids and as sustainable composite coagulants are also discussed in this analytical report. Keywords: Turbidity; Biocoagulants; Natural; Dosage

Evaluation of the self-assembled functional PPFS-P-AM composite for treating oilfield sewage

Oilfield sewage has a complex composition with large amounts of emulsified oils, polymers and surfactants. Efficient coagulants are required to purify such sewage to meet emissions standards. In this study, oxidized FeSO4·7H2O and NaHCO3were condensed by basic titration and polyferric sulfate phosphate (PPFS) was prepared by the addition of NaH2PO4·2H2O to improve its charge and stability. In addition, by adding modified palygorskite and cationic amylum, a functional polyferric sulfate phosphate, palygorskite and cationic amylum copolymer (PPFS-P-AM) composite coagulant was synthesized through self-assembly, and then used to treat oilfield sewage. The characteristic functional groups and crystal forms of the coagulant were characterized by FTIR and XRD. The zeta potential and radius of gyration (Rh) indicate that the introduction of palygorskite and cationic amylum enhance the charge neutralization and bridging adsorption abilities, respectively. The optimal dosage of cationic amylum is 5% in 80 mg·L−1 PPFS-P-AM, which provides turbidity and oil removal rates of 98% and 94%, respectively. Observation by SEM shows that the micro-morphology of PPFS-P-AM flocs has adendritic distribution with a reticular macromolecular structure that provides good sweeping performance during the sedimentation process. Finally, an analysis of its properties and performance reveals the mechanism by which PPFS-P-AM coagulates oilfield sewage. PPFS-P-AM provides better coagulation than the other studied coagulants via the synergistic effects of reinforced charge neutralization, bridging adsorption and sweeping.

Design and coagulation mechanism of a new functional composite coagulant in removing humic acid

The deep removal of organic pollutants is a challenging task for coagulation technology in the drinking water and wastewater treatment plants to satisfy the rising water standards. To obtain high removal efficiency for organic matter (OM), a novel coagulant, Fe-PAA, was developed based on ferric salts and polyacrylic acid (PAA) in this study, which contained long flexible carbon chain and positive coordination sites. The humic acid (HA) was employed as a representative OM target with wide molecular weight range in the coagulation tests. The coagulant Fe-PAA with Fe3+/COOH ratio of 1:1 exhibited the promising coagulation performance meeting with the initial design principle. Compared to ferric chloride, Fe-PAA-1:1 exhibited overall advantages on HA removal, formation of large and compact flocs, and control of residual Fe3+. As a macromolecular coagulant, Fe-PAA-1:1 demonstrated the synergetic advantages of iron hydrolysis components and flexible long-chain polymers. The charge neutralization and bridging effects dominated coagulation process under acidic condition, while complexation and bridging effects were the main driving force of Fe-PAA-1:1 under neutral and alkaline conditions for HA removal. Overall, this study provides revelatory information for the development of a new kind of highly efficient and cost-effective coagulant to satisfy the demand of current water treatment.

Leaching of coal fly ash with sulphuric acid for synthesis of wastewater treatment composite coagulant

ABSTRACT The results of leaching of coal fly ash in H2SO4 solution are presented. The effects of leaching time, H2SO4 concentration, temperature, and solid/liquid ratio were explored for the dissolution process. Particle size distribution results showed that changes in particle size occurred during the dissolution process; XRD, XRF and FTIR results indicated the same characteristics of the mineral matter in the raw and treated coal fly ash samples; and SEM showed that the raw coal fly ash particles have smooth spherical surfaces while a pricked and corroded surface and a stem-like structure were formed after leaching. The dissolution rate of coal fly ash is controlled by mixed-controlled mechanism (diffusion and chemical reaction). The corresponding activation energies were calculated to be 59.8 kJ/mol for iron, 7.3 kJ/mol for aluminium and 5.8 kJ/mol for silicon. The reaction order was determined to be zero order kinetic model.

The interactions between Al (III) and Ti (IV) in the composite coagulant polyaluminum-titanium chloride

• Novel polyaluminum-titanium chloride composites were synthesized. • The interactions between Al and Ti in PATC were confirmed. • The introduction of Ti influenced the species distribution of Al. • PATC had high positive charges and large molecular weights. • The existence of Ti in PATC improved its coagulation performance. Safe and effective coagulants are necessary for surface water treatment. The polyaluminum-titanium chloride (PATC) composite coagulant has promise but its application is limited due to the lack of fundamental theoretical research. We prepared a series of novel PATCs and investigated the effects of the interaction between Al (III) and Ti (IV) on the chemical species distribution, physicochemical properties and coagulation efficiencies. The Al-O-Ti bonds observed in the PATC infrared spectra were predicted by density functional theory computation to appear in 4-atom rings in the structure. The differences in Al species distribution of PATC and PAC illustrated that the introduction of Ti retarded the hydrolysis of monomeric Al species (Al a ) and medium polymerized Al species (Al b ) to colloidal Al species (Al c ) at low B levels, but the transformation was promoted at high basicities (B). PATCs exhibited higher charge densities and larger molecular weights than PAC at the same B levels, which contributed to their excellent coagulation efficiencies. PATC with low B values but high Al/Ti molar ratios mainly provided charge neutralization in removal of humic acid kaolin, while the dominant coagulation mechanism converted from charge neutralization to sweeping and bridging effects at high B values or low Al/Ti molar ratios.

Enhancing fine particle separation by hybrid-electrostatic-turbulence coagulation: An experimental and numerical investigation

The electrostatic precipitator(ESP) has low efficiency in removing sub-micron particles. Coagulation technology, as a fine particle pretreatment technology, uses an external effect to agglomerate and grow fine particles, increase the average particle size, and make it easier to remove by subsequent dust removal equipment. However, the coagulation efficiency of a single coagulation technology is limited. Aiming at the particle charging mechanism and coagulation mechanism in the electric/turbulent composite coagulation process of fine particles, this paper uses a combination of numerical simulation and experiment to study the effects of different structural parameters, discharge parameters and flue gas parameters on corona discharge and particle charge. On this basis, the coagulation characteristics of charged particles in the turbulent flow field are studied. The results show that, when the Angle between the tip of the arista electrode is 90°, the corona discharge effect is the best. With the increase of supply voltage and temperature, the charge of particles increases. When the applied positive voltage is 29 kV and negative voltage is −35 kV, the total coagulation coalescence efficiency of fine particles reaches the maximum. The coagulation efficiency increases with the increase of temperature, but decreases with the increase of inlet flow rate.

Coagulation performance and floc characteristics of poly-ferric-titanium-silicate-chloride in coking wastewater treatment

A novel composite coagulant poly-ferric-titanium-silicate-chloride was synthesized and employed to treat one typical kind of industrial wastewater-coking wastewater. In this study, two composite coagulants, poly-ferric-titanium-silicate-chloride (PFTSC) and poly-titanium-silicate-chloride (PTSC), were prepared and employed to treat coking wastewater. The structure and morphology of the prepared PFTSC and PTSC were examined, and the compositions of the organic matter were characterized in the coking wastewater samples. Changes in the flocs were monitored during coagulation. The kinetic model of floc sedimentation was preliminarily investigated. We observed the formation of new Fe-O-Si and Ti-O-Si bonds: PFTSC showed a higher organic removal efficiency and turbidity than PTSC; PFTSC removed ≥ 93% of the turbidity in the coking wastewater. Based on the dissolved organic carbon, chemical oxygen demand, and ultraviolet absorbance at 254 nm characteristics, the corresponding organic matter removal rates were 24.1%, 10.7%, and 10.1%, respectively. PFTSC can target the removal of toxic organic compounds. Compared with PTSC, PFTSC flocs had a more compact structure and higher porosity, which indicated that PFTSC had a stronger removal capacity for suspended solids and organic matter. Floc sedimentation was suitable for fitting with the quasi-second-order kinetics model in the process of coking wastewater treatment. This study indicates that PFTSC is a prospective candidate for the pretreatment of industrial coking water, such as coking wastewater.

Flocculation Performance of Pcfa Composite Coagulant for Removing Nanoparticles

Flocculation Performance of Pcfa Composite Coagulant for Removing Nanoparticles

Coagulation performance of Al/Fe based covalently bonded composite coagulants for algae removal

A novel covalently bonded composite coagulant CAFM was synthesized by using inorganic PAFC and organic CPAM through UV initiation. The algae and turbidity removal efficiency were investigated by using CAFM in algae-laden water coagulation process. The Al/Fe residual and algae flocs size were also examined. Results showed that 96% chlorophyll a and 87% turbidity were removed by using CAFM at dosage of 40 mg/L. The removal efficiency was larger than that by using PAFC or CPAM at their optimal dosage. The minimum Al residual of 12.47 μg/L, Fe residual of 9.64 μg/L together with the most compact algae flocs were achieved by using CAFM0.6, which was great favorable and essential for drinking water treatment. Finally, the charge neutralization of PAFC and bridging of CPAM synergetic contributed to algae harvesting.

Copper oxide nanoparticles removal by coagulation and optimization by matter–element analysis model

Nanoparticles have been inspected in water environment and sewage treatment plants, but how to achieve efficient removal of them through existing treatment processes is a potential issue. In this study, the organic–inorganic composite coagulant (PAC-CA) was applied to remove copper oxide nanoparticles (CuO-NPs) and study their coagulation behavior and the characteristics of flocs produced by coagulation. Under the optimal coagulation conditions with a dosage of 25 mg/L, pH of 7, stirring intensity of 200 s−1, and settling time of 15 min, the removal rates of CuO-NPs and turbidity were 89.83% and 93.51%, respectively. Zeta potential studies show that the main action mechanism of PAC-CA under low dosage or alkaline conditions is charge neutralization, and under high dosage or acidic conditions, the main action mechanism is adsorption bridging. A matter–element analysis model was established based on the evaluation index of stirring intensity, kaolin concentration, humic acid concentration, initial CuO-NPs concentration, pH, PAC-CA dosage, turbidity removal rate, and CuO-NPs removal rate. Kaolin can promote the removal of CuO-NPs and turbidity by PAC-CA. The main action mechanisms of PAC-CA are charge neutralization and adsorption bridging. PAC-CA has good coagulation performance for CuO-NPs wastewater, and provides a theoretical basis for the practical engineering application of coagulation for removing nanoparticles in wastewater.

Study of aluminium speciation in the coagulant composite of polyaluminium chloride-chitosan for the optimization of drinking water treatment

The control of aluminium speciation in coagulant composites is the appropriate approach to remove turbidity and natural organic matter from raw water effectively. This suspended matter in water affects its organoleptic quality and triggers problems by causing interference with the water treatment process. This study examined the behaviour of composite coagulants polyaluminium chloride-chitosan (PAC-CTS) with different aluminium speciation and polymer ratio to remove oxidizable matter and turbidity residing in surface waters. The fraction of basicity ratio (Al/OH) in the preparation of polyaluminium chloride (PAC) and chitosan (CTS) were simultaneously evaluated and optimized according to aluminium speciation by experimental design. The interaction between PAC and CTS was examined via Al-Ferron timed spectrophotometric approach, theoretical study and fourier transform infrared (FTIR) analysis. Ferron analyses reveal that basicity ratio and CTS fraction affect the distribution of aluminium forms (mononuclear Ala, medium polymeric Alb, colloidal, and high polymeric Alc) in PAC-CTS. The theoretical study showed that Al(OH)2+, Al13, and Al30 species are more reactive than aluminium hydroxide Al(OH)3 at different magnitudes and sites with chitosan. The FTIR analysis confirmed the existence of an interaction between PAC and CTS by revealing a new peak for Al-NH2 stretches. The coagulation performance study of composite coagulant PAC-CTS with different compositions showed that the increase of chitosan and the preponderance of Alb and Alc species compared to Ala are suitable for removing colloidal suspensions. Further, incorporation of PAC with high basicity (74.1%) in 16.3% of chitosan (PAC-CTS1) removed 99.51% of turbidity and 66.66% of oxidizable matter at AlCl3 concentration of 10 mg l−1. However, increasing the percentage of chitosan to 34.1% at the same basicity (74.1%) in the PAC-CTS4 compound was not beneficial for oxidizable matter removal. It was speculated that the improvement in coagulation performance could be achieved by considering the aluminum speciation and polymer content in the composite flocculant PAC-CTS. The present work could be a useful model for synthesizing and studying organometallic interactions in developing new composite coagulants to improve coagulation performance.

Performance evaluation of composite coagulant in treating textile wastewater

Our modernized world needs colourful cloths. As per the requirements we need textile industries to fulfil the demands. These industries need a huge quantity of freshwater for dyeing. As a result, a large amount of wastewater is released. The released wastewater starts to contaminate natural sources and leads to several serious environmental health problems. Coagulation is one of the techniques which is used to treat all these wastewaters of various industries. In this paper, a composite coagulant of Polyaluminium chloride (PACl) and polyamine is used to remove colour of the textile wastewater. The optimum coagulant dosage and pH values were determined by comparing colour removal efficiency. It was found that 1:1 ratio gives the optimum result at pH 5 for the optimum dosage of 600 mg/L with the 95% decolourisation. Finally, the treatment of the actual textile wastewater has shown that PACl-polyamine is an effective composite coagulant.

Comparisons of coagulation efficiency of conventional aluminium sulfate and enhanced composite aluminium sulfate/polydimethyldiallylammonium chloride coagulants coupled with rapid sand filtration

Conventional aluminium sulfate (AS) coagulant's inability to effectively meet stringent water quality requirements have created the need to explore enhanced composite coagulants. The coagulation efficiency of AS and composite AS and polydimethyldiallylammonium chloride (AS/PDMDAAC) coagulants were investigated using jar test and then, coupled with rapid sand filtration (RSF). The various composite AS/PDMDAAC at different intrinsic viscosity of PDMDAAC and mass ratio of PDMDAAC to AS in coagulant solutions were optimized and operated at same supernatant turbidity (SST) or same dosage mode (SD). The results showed about 7–10% reduction in dosage for all composite AS/PDMDAAC and also improved water qualities compared to AS only. The patterns of water quality improvements at lower (0.65 dL/g), medium (1.60 dL/g), and higher (2.60 dL/g) intrinsic viscosity of cationic polymer PDMDAAC among different mass ratio of PDMDAAC to AS in the composite mixtures were 5:1 > 20:1 > 10:1; 10:1 ≥ 5:1 > 20:1; 20:1 > 10:1 > 5:1 respectively. The percentage removal efficiencies for AS and optimal composite coagulant at intrinsic viscosity (1.60 dL/g) and mass ratio (10:1) operated at SST or SD after filtration for CODMn, NH3N and turbidity were (71.20, 72.72, 73.33%); (69.15, 69.23, 73.08%) and (93.89, 95.07, 97.26%) respectively. It was concluded that enhanced composite AS/PDMDAAC coagulants operated at SST mode showed significant water quality improvement than conventional AS having 7% and 31.8% for COD and NH3N removal while operational mode at SD produced more significant water quality improvements than conventional AS with 9.49%, 45.45%, and 39.55% for COD, NH3N, and turbidity removal before filtration respectively. More importantly, all composite AS/PDMDAAC met stringent water quality requirements before and after filtration. This research provided new insight about application of economical and effective alternative composite AS/PDMDAAC coagulant useful in the treatment of water for large population.

Preparation of polyaluminum zirconium silicate coagulant and its performance in water treatment

A novel type of inorganic polymer coagulant, polyaluminum zirconium silicate sulfate (PAZS), was synthesized via co-polymerization. In the treatment of kaolin-humic acid synthetic water, it was found to be most effective when Si/(Zr + Al) = 1, OH/(Al + Zr) = 0.1, and Al/Zr = 3. Through CCD design, zeta potential and floc analysis, PAZS showed excellent coagulation and sedimentation performance in an experimental pH range of 3∼8. The prepared composite coagulant PAZS was characterized by FTIR, XRD, and SEM. Results indicate that PAZS is a highly polymerized complex with rough folded surfaces. The adsorption bridging effect and charge characteristics enabled PAZS to function in an acidic environment. The findings from the research conducted indicate that PAZS is a promising coagulant for efficient water treatment.

Synthesis and Application of a Novel Composite Coagulant Aid from Rice Starch and Sesbania Seed Gum for Water Treatment

This study evaluated the feasibility of a newly synthesized composite coagulant aid, SSG-S for turbidity removal in drinking water treatment. SSG-S was synthesized from rice starch and sesbania seed gum through the microwave irradiation method. The surface morphology of SSG-S was evaluated through scanning electron microscope (SEM). Compared with conventional rice starch, SSG-S provides more porous sites and longer chains for effective pollutant adsorption and bridging processes. Moreover, response surface methodology (RSM) revealed that the addition of SSG-S increased the turbidity reduction rate up to 96.3%. In addition, the novel coagulant aid helped to reduce the dosage of alum, coagulant aid, and settling period by  6.7%, 87.9%, and 6.5 minutes (1.5 times quicker), respectively.