Organic Flocculants Research Articles

Construction and Application of Flocculation and Destability System of Biodrill-A Drilling Fluid in Bohai Oilfield

To protect the marine ecological environment of Bohai Bay, the waste drilling fluid in Bohai oilfield have to be treated. In the light of the composition characteristics of Biodrill-A drilling fluid, the compounding method of the inorganic–organic flocculants was adopted to assist the flocculation and solid–fluid separation of Biodrill-A drilling fluid. Through the orthogonal test design, the main factors impacting the flocculation effect on Biodrill-A drilling fluid were found to the concentration of inorganic flocculant CaCl2 and the flocculation pH value. The optimal flocculation treatment was further obtained through single-factor optimization. Specifically, when the inorganic flocculant CaCl2 concentration was 0.9 w/v%, the organic flocculant concentration was 0.01 w/v%, the flocculation pH was 8, and the flocculation time was 7 min. Eventually, the final dewatering rate could reach 84.02%. In the optimized compound flocculants, the inorganic flocculant CaCl2 reduced the zeta potential of clay particles by electric neutralization to decrease the repulsion among particles, and the organic one could absorb and wrap the clay particles through bridging curling and electric neutralization after flocculation destabilization. Both inorganic and organic flocculants facilitated the large flocs and particles of clay particles. The field test showed that the inorganic–organic flocculants were suitable for the on-line flocculation treatment process based on centrifugal machine. The waste drilling fluid was reduced by 82%, and the water content of the separated solid phase was as low as 25.7%.

Comparison of two cationic chitosan-based flocculants prepared by photocatalysis and photoinitiation systems: Synthesis mechanism, structure and performance in water treatment

• The copolymerization reaction was separately initiated by photocatalyst and photoinitiator. • The initiation and synthesis mechanisms of CS-g-DAC (T) and CS-g-DAC (V) were different. • CS-g-DAC (V) prepared by V A-044 owned the little higher initiation efficiency than CS-g-DAC (T) . • The ratio of C-N to C = N in the molecular structure of CS-g-DAC (T) was lower. • CS-g-DAC (T) possessed the little more outstanding performances in water treatment. Flocculants as the traditional water treatment agents were widely applied in water treatment, sludge thickening and dewatering, oil exploitation and papermaking. The synthesis of organic polymer flocculants via high-efficient initiation system has aroused special attention in the development of flocculant. Herein, a chitosan-based flocculant (CS-g-DAC (T) ) was synthesized through ultraviolet (UV) initiation of titanium dioxide (TiO 2 ) It was compared with other chitosan-based flocculant (CS-g-DAC (V) ) synthesized by a traditional photoinitiator, V A-044 , in terms of initiation efficiency, initiation mechanism, flocculant characteristics, molecular structures and flocculant performances in water treatment. Holes (h + ), superoxide radicals (O 2 • - ) and hydroxyl radicals ( OH) were generated in the initiation processes of TiO 2 and V A-044 . TiO 2 generated more O 2 • - and less OH compared with V A-044 . CS-g-DAC (T) owned the higher ratio of C = N to C-N in molecular structure, the little higher removal efficiency in water treatment and larger floc size than CS-g-DAC (V) . The effect of charge neutralization of CS-g-DAC (T) and CS-g-DAC (V) were close. TiO 2 possessed the potential to substitute the traditional photoinitiator in synthesis of organic polymer flocculants and improved the molecular structure and flocculation efficiency of flocculants.

Enhanced coagulation for TiO2-NPs removal by using a hybrid flocculant

A hybrid flocculant, PAC-CA, with the advantages of inorganic and organic flocculants, was prepared, and the coagulation behavior and floc characteristics of PAC-CA for removing titanium dioxide nanoparticles (TiO2-NPs) under different conditions were studied. The effects of monomer mass ratio, initiator concentration, hydroxyl aluminum ratio, reaction temperature, and polymerization time on the coagulation performance for TiO2-NP removal were studied. PAC-CA was characterized through SEM, FT-IR, TG-DSC, XRD, XPS, and Ferron complex colorimetric characterization. The characterization results showed that PAC-CA was successfully copolymerized using AlCl3, carboxymethyl chitosan, and acrylamide. The high content of Alb in PAC-CA helped improve the coagulation performance. When the dosage was 30 mg/L, the pH was 8, the stirring intensity was 200 s−1, and the settling time was 30 min, the optimal removal rates for TiO2-NPs and turbidity were 87.30% and 91.72%, respectively. Kaolin could effectively improve the TiO2-NP removal efficiency and promote the density and particle size of flocs. Humic acid exerted an inhibitory effect on coagulation efficiency with loose and small flocs.

Aspergillus oryzae, a novel eco-friendly fungal bioflocculant for turbid drinking water treatment

• An eco-friendly fungal bioflocculant was developed for turbid water purification. • More than 85% turbidity can be removed in a wide pH value (4.0–9.0). • Adsorption and charge attraction played dominant role in flocculation process. • The functional groups on fungal pellets contributed to turbidity flocculation. • Fungal pellet can be directly used as bioflocculant rather than fungal metabolites. The residuals of aluminum (Al), iron (Fe), and acrylamide are always present when traditional inorganic coagulants and organic polyacrylamide flocculants are used, causing environmental security problems. Nevertheless, most microbial flocculants are nontoxic, cause no secondary pollution, and easily biodegrade, and thus efficient and eco-friendly bioflocculants are valuable. Herein, Aspergillus oryzae , a food fermentation fungus, was cultured and developed as a bioflocculant for turbid drinking water treatment. The physical and chemical structures of A. oryzae was characterized, and flocculation performance was evaluated in turbid drinking water treatment. Flocculation efficiency of 91.09% was obtained in the fungal pellets at a culture time of 72 h, flocculant dosage of 3.2 g/L, and pH of 5.0. More than 85% flocculation efficiency was achieved in a wide pH range from 4.0 to 9.0. The removal mechanism was investigated through zeta potential, field emission scanning electron microscopy, Fourier transform infrared spectrometry, X-ray photoelectron spectroscopy, and X-ray diffraction analysis. Results showed that functional groups, such as hydroxyl, amide, and carboxyl, in the metabolites secreted by the fungal pellets contributed to the flocculation process through adsorption. Zeta potential analysis indicated that electrostatic force contributed a positive effect. Fungal hyphae can be directly used as bioflocculants rather than fungal metabolites. This feature is favorable and convenient to drinking water treatment.

Research Progress on Oil Sludge Treatment in Oilfield: A Mini-Review

: A large amount of sludge produced in the processing of crude oil has brought great harm. In this paper, common flocculants are summarized. According to the treatment process of crude oil, flocculants are divided into organic flocculants, inorganic flocculants, microbial flocculants, composite flocculants, and magnetic flocculants. The mechanism and limitation of each flocculation on crude oil sludge were analyzed. Finally, it is pointed out that the flocculation process of sludge is complex, and the development of new flocculant with high efficiency, safety, and economy is the main trend of flocculant development in the future.

Cleaning of concentrated emulsion sewage of electric-weld pipe lines

Existing processes of cleaning emulsion sewage are based on either physicochemical technology with application of complex of reagents – nonorganic electrolytes and organic flocculants, resulting in obtaining highly-mineralized purified water, which cannot be used for technical water supply, or based on complicated technologies of electrocoagulation and ultrafiltration. This required elaboration of a new technology and equipment for cleaning concentrated emulsion sewage, in particular, those containing emulsol of Wedolit EP-5 grade, used for hydro-mechanical expanders of electric-weld pipe lines. The technology stipulates a successive introduction of a reagent – suspension of alumo-silicate based hard-phased sorbent and solution of flocculant of cation type Praestol-650ВС – into emulsion sewage, their mixing with emulsion water in a definite mode, sedimental differentiation of the formed phases in a precipitator-flocculator “ЭП ОФ”, gravitation concentration and dewatering of the obtained sediment at vacuumfilter. The dewatered sediment can be utilized in cement industry and metallurgy. It was shown that application of the hard-phase sorbent does not result in an increase of mineralization of purified water and enables to use it for technical purposes. The group of companies “ECO-PROJECT”, Ekaterinburg, accomplished a project for Chelyabinsk pipe-rolling plant, elaboration and manufacturing of equipment, as well as commissioning and start-up of the equipment. The elaborated technical solutions in the process of equipment running showed a high efficiency and can be used as a base for creation of facilities of any productivity for cleaning multi-type emulsion sewage at enterprises of various industries.

Synergetic Effect of Organic Flocculant and Montmorillonite Clay on the Removal of Nano-CuO by Coagulation-Flocculation-Sedimentation Process.

The widespread usage of nano-copper oxide particles (nano-CuO) in several industrial products and applications raises concerns about their release into water bodies. Thus, their elimination from drinking water is essential to reduce the risk to human health. This work investigated the removal of nano-CuO from pure water and montmorillonite clay (MC) suspensions using poly aluminum ferric chloride (PAFC) as well as cationic polyacrylamide (PAM) by the coagulation-flocculation-sedimentation (C/F/S) process. Moreover, the PAFC and PAFC/PAM flocculation performance for various nano-CuO particles concentrations, dosages, pH, settling times and stirring speeds were also investigated. The findings showed that the removal of nano-CuO and turbidity in MC suspension were higher as compared to pure water. Moreover, the combined effect of PAFC/PAM on the elimination of nano-CuO and turbidity was also substantially better than the individual use of PAFC or PAM. The efficient removal of CuO was observed in the solution containing higher mass concentration in the order (10 mg/L > 2.5 mg/L > 1 mg/L) with an increased coagulant dose. The improved removal performance of nano-CuO was observed in a pH range of 7–11 under various water matrices. The C/F/S conditions of nano-CuO were further optimized by the Box–Behnken statistical experiment design and response surface methodology. The PAFC/PAM dose resulted in the maximum removal of nano-CuO (10 mg/L) in both pure water (>97%) and MC suspension (>99%). The results of particle monitoring and Fourier transform infrared of composite flocs revealed that the main removal mechanism of nano-CuO may be the combined effect of neutralization, complexation as well as adsorption.

Application of high molecular weight flocculants for the purification of oily waters

In flotation separators, to intensify the purification process, the method of preliminary reagent treatment is used with a combination of solutions of mineral coagulants and organic flocculants. This method causes the corrosive activity of water, a significant amount of sediment, and secondary water pollution with products of hydrolysis of mineral salts. The above disadvantages are nnot typical of the method of preliminary treatment of oily waters with ionogenic high-molecular flocculants, which is used in the practice of coastal treatment of oily waters. The paper presents the results of the experimental studies on the use of high-molecular flocculants for the preliminary reagent treatment of bilge water sent to the flotation unit. The following high-molecular flocculants were investigated: Praestol 852, Praestol 853, Praestol 2540. It was found that Praestol 853 provides the highest degree of oil pollution recovery from the bilge water solution. The fractional composition of oil products in bilge water was analyzed before and after cleaning. It was determined that in the flotation cleaning, coarse and medium-dispersed particles of oil pollution are completely extracted.

Physicochemical characterization and flocculation performance evaluation ofPAC/PMAPTACcomposite flocculant

AbstractA novel inorganic–organic composite flocculant was prepared with polyaluminum chloride (PAC) and poly(methacrylamido propyl trimethyl ammonium chloride) (PMAPTAC). To understand the physicochemical characterization of PAC/PMAPTAC and evaluate its flocculation efficiency, the interactions of PAC and cationic polymer were investigated, then the characterization and flocculation performance of PAC/PMAPTAC and PAC/Poly‐dimethyldiallylammonium chloride (PDMDAAC) were compared. The results showed that there were obvious interactions between PAC and cationic polymer in composite flocculant. The cationic polymer chain exhibited a coiled state in PAC solution, and the curly degree of PMAPTAC chain was lower than that of PDMDAAC due to the intermolecular association of methyl of PMAPTAC. The cationic polymer enhanced the charge neutralization ability of PAC and changed the aluminum hydrolysis polymerization species of PAC from low and medium polymeric species to high‐polymeric species. The flocculation sedimentation experiments turned out that the charge neutralization and bridging ability of PAC/PMAPTAC was higher than that of PAC/PDMDAAC, and the increase of molecular weight or content of PMAPTAC in PAC/PMAPTAC could enhance the charge neutralization and adsorption bridging ability simultaneously. The enhanced effects may come from the exist of polymer and the interactions between PAC and cationic polymer in composite flocculant.

Synthesis of a new polyunsaturated cationic crosslinker by a new micro‐polycondensation reaction as a critical modifier of polycationic flocculant for purifying dyeing wastewater

AbstractBACKGROUNDThis work explored a complete evolutionary process, from discovering a new reaction and synthesizing a new crosslinker intermediate, to product application in the purification of dyeing wastewater.RESULTSA new micro‐polycondensation reaction between propylacryloyloxypropyldimethylamine and epichlorohydrin was first observed, forming a new polyunsaturated cationic crosslinker (poly (2‐hydroxypropylacryloyloxypropyldimethylammonium chloride) (PHPAC), abbreviating HPAC unit as the repeating unit); meanwhile, this new PHPAC crosslinker was just a critical modifier of a polycationic flocculant. When the thimbleful of PHPAC crosslinkers containing only 0.2% molar percentage of HPAC units were incorporated into a polycationic skeleton of poly (acryloyloxyethyltrimethylammonium chloride) (PDAC), the application properties of the obtained modified product (known as SC‐PDAC) were greatly improved compared to the unmodified product of PDAC. The cost for preparing the modified product of SC‐PDAC was hardly increased because the quantity of HPAC modifier used was minimal. The multi‐dimension flocculation interactions of SC‐PDAC with the anionic dyes allowed the SC‐PDAC to realize a more efficient purification of dyeing wastewater than the unmodified PDAC. The obtained SC‐PDAC could remove 99.10% of the dyes Reactive Scarlet 3BS and 96.69% of the dyes Methyl Blue when used for purifying the dyeing wastewater. In real engineering applications, the further complex interactions of SC‐PDAC with certain inorganic flocculants and coagulant aids would allow the flocs to be quickly formed, condensed, and aggregated, so as to realize a fast purification of dyeing wastewater within 10 s. The successful implementation of a simulation amplification experiment for treating a 4.0 L dye solution further confirmed that the SC‐PDAC had good potential to be applied in real water treatment engineering.CONCLUSIONSTherefore, as expected, it could be regarded as an economic and facile modification way to obtain the efficient organic cationic flocculant by selecting the PHPAC crosslinker as a critical modifier. © 2021 Society of Chemical Industry (SCI).

Biopolymer-based flocculants: a review of recent technologies.

Biopolymer-based flocculants have become a potential substitute for inorganic coagulants and synthetic organic flocculants due to their wide natural reserves, environmental friendliness, easy natural degradation, and high material safety. In recent years, with more and more attention to clean technologies, a lot of researches on the modification and application of biopolymer-based flocculants have been carried out. The present paper reviews the latest important information about the base materials of biopolymer-based flocculants, including chitosan, starch, cellulose, and lignin etc. This review also highlights the various modification methods of these base materials according to reaction types in detail. Via the recent researches, the flocculation mechanisms of biopolymer-based flocculants, such as adsorption, bridging, charge neutralization, net trapping, and sweeping, as well as, some other special mechanisms are comprehensively summarized. This paper also focuses on the water treatment conditions, the removal efficiency, and advantages of biopolymer-based flocculants in applications. Further, this review sheds light on the future perspectives of biopolymer-based flocculants, which may make progress in the sources of base materials, modification processes, multi-function, and deepening application researches. We believe that this review can guide the further researches and developments of biopolymer-based flocculants in the future, to develop them with a higher efficiency, a lower cost, more safety, and multi-function for more diversified applications. Graphical abstract

Characterization and flocculation evaluation of a new organic–inorganic hybrid polymer flocculant (PAC‐AM‐DMC)

AbstractA novel organic–inorganic hybrid flocculant PAC‐AM‐DMC is synthesized using potassium persulfate as an initiator, which was used in industrial wastewater treatment. Comparing with the traditional inorganic flocculant, this new flocculant has the advantage of low dosage and high efficiency. Simultaneously, it is less toxic and more environmentally friendly than the organic flocculant. The organic–inorganic hybrid flocculant PAC‐AM‐DMC demonstrates better flocculation than the commercial single type flocculant (PAC, PAM), and the effect is better than simply combining the two flocculants. It has potential for commercialization. When PAC:(AM + DMC) = 2:8, the initiator is 0.2 wt%, and the flocculant obtained by reacting at 50°C for 4 h has the best effect on sewage treatment. When the pH is 7, the treatment effect of PAC‐AM‐DMC is best with the dosage of 10 ppm. Correspondingly, the amount of flocculant is 10 mg/L, and the turbidity of simulated sewage is 172 nephelometric turbidity unit (NTU), which is over 98% of turbidity removal efficiency. In addition, the prepared hybrid flocculant is nearly non‐corrosive and posed little damage to the equipment. And the hybrid flocculant has excellent salt resistance.

The use of natural organic flocculants for harvesting microalgae grown in municipal wastewater at different culture densities.

Harvesting microalgae from liquid culture is a difficult issue to solve and is most commonly done through settling. However, settling is a slow process on its own and generally needs to be induced chemically or by introducing stress to the culture. Polymeric, cationic substances, such as cationised starch and chitosan, are often used for flocculation and settling. These large, positively charged molecules form large clusters with suspended particles in the liquid medium. In the present study, three natural organic flocculants (cationic starch, chitosan and acacia tannin S5T) were tested to harvest microalgal cultures grown in wastewater. Two microalgal species, one strain of Chlorella vulgaris and one strain of Scenedesmus obliquus, were cultured in municipal wastewater for different lengths of time, and settled using either cationic starch, chitosan or acacia tannin S5T. Results indicated that S5T worked with approximately the same efficiency in the two assayed species, although it requires a relatively high dosage to function (about 300 mg L-1 ), while the other two flocculants varied from species to species.

Sedimentation Behavior of Organic, Inorganic, and Composite Flocculant-Treated Waste Slurry from Construction Works

The disposal of waste slurry from construction engineering is attracting more and more attention due to the thorny issues related to high water content (dewatering is difficult and time-consuming). The use of chemical flocculants is proposed in this study, and organic, inorganic, and composite flocculant are designed to identify the characteristics and efficiency of slurry-water separation. The influence of flocculant type and dosage on slurry settlement and its associated mechanisms are studied by a set of sedimentation column, particle size distribution, and scanning electron microscopy (SEM) tests. The experimental results prove that organic, inorganic, and composite flocculants can promote the efficiency of slurry-water separation, although inorganic flocculants may perform relatively worse in comparison with organic and composite flocculants. The conditioning performance of organic flocculants is sequentially anionic polyacrylamide (APAM) > polyacrylamide (PAM) > amphoteric polyacrylamide (ACPAM) > cationic polyacrylamide (CPAM), while their optimum dosage is 300, 300, 400, and 400 mg/L, respectively. The combined formulation of APAM+FeCl3 improves the conditioning of slurry owing to the charge neutralization, net capturing, and sweeping ability. The flocculating effect causes an aggregation of fine particles, and this induces a decrease in the amount of fine particles and an increase in the fraction of coarse flocs. The SEM results prove that the slurry particles tend to be arranged in a parallel manner and the flocculant induces an agglomeration of fine particles owning to a series of physicochemical reactions. The previous discussions can provide an experimental framework for the development of slurry-water separation technology on waste slurry from construction works.

Harvesting Aurantiochytrium sp. SW1 using organic flocculants and characteristics of the extracted oil

The use of microalgae as an alternative source of biofuel production has become an emerging topic of interest in recent years. However, the main challenge in the microalgae downstream process lies in the separation of microalgae from the growth media (harvesting process). This study proposed the use of different organic flocculants, namely, cationic guar gum, gum arabic and okra gum, to harvest the microalga Aurantiochytrium sp. SW1 for subsequent extraction of docosahexaenoic acid-rich oil from the microalgae. The physicochemical properties and bioactivities of the cell and extracted oil were studied. The results showed that cationic guar gum at 0.5% w/v and gum arabic at 0.1% w/v were the optimum concentrations for cell harvesting. The highest cell recovery was achieved using cationic guar gum with up to 12.8 g/L culture, which was 3.8-fold higher than that of the control method, probably due to the cationic charge of the cationic guar gum, which exhibited a greater efficiency in coagulating the negatively charged surface of microalgae. Overall, the different flocculants used during harvesting affect the extraction efficiency of lipids and other phytochemicals in the cells. Cationic guar gum significantly produced the highest (p ≤ 0.05) oil yield extracted from the culture, which was up to 25.06% w/w biomass. Interestingly, the significantly highest (p ≤ 0.05) total phenolic content (0.23 ± 0.01 mg gallic acid equivalent/mL) and carotene content (1.67 ± 0.42 mg/mL) were observed in microalgae oil flocculated with okra gum, signifying that the type of flocculant affected the determination of phytochemical content of the extracted oil. The oil obtained from okra gum flocculant also exhibited the highest 2,2-diphenyl-1-picrylhydrazyl scavenging activity (0.89 ± 0.01 mg Trolox equivalent/mL) and ferric reducing antioxidant powder (26.77 ± 1.52 mg Trolox equivalent/mL), which was attributed to the higher concentrations of phenolic compounds and carotene content. This work reveals the potential usage of okra gum as a flocculant with enhanced phytochemical contents and bioactivities.

Mechanistic insights into chemical conditioning by polyacrylamide with different charge densities and its impacts on sludge dewaterability

While chemical conditioning has been widely used to improve the sludge dewaterability, the knowledge gap in understanding the detailed interaction between the agent and sludge as well as the structural properties of the conditioned flocs remains. In this study, we therefore investigate the mechanisms of sludge conditioning with a widely used organic flocculant, polyacrylamide (PAM), by using a suite of time-resolved characterization technologies. Compared to PAM with a low charge density, the high charge-density PAM (70%) improves the sludge flocculation and apparent filtration performance as a result of the enhanced structural strength. This is mainly attributed to the bonding between the biomolecules and PAM, resulting in the aggregation of flocs, squeezing of the water dispersed among the sludge particles and finally improvement of the dewaterability. The interaction between sludge and PAM is dynamically assessed by multiple light scattering spectroscopy and quartz crystal microbalance with dissipation. Results demonstrate that the use of high charge-density PAM quickly generates flocs with a rigid and dense structure that suffer less from the hydraulic turbulence. These findings provide mechanistic insights into the interaction between sludge and flocculant/coagulant (of different charge densities) and its impacts on the floc properties, which is beneficial to the process design and optimization for sludge conditioning, pipeline transport and dewatering in high-pressure systems.

Preparation of organic polymer flocculant and its application in drilling fluid

A flocculant (DES0-0) was synthesized by epichlorohydrin and diethylamine, followed by adding crosslinking agent such as ethylenediamine, diethylenetriamine and triethylenetriamine to obtain the crosslinked polymer DES0-1, DES0-2, DES0-3. The flocculation effect of DES0-1, DES0-2, DES0-3 and PAM was studied by measuring the volume, transmittance and particle size of the clarified solution after flocculation. The results showed that the flocculation effect of triethylenetetramine crosslinked polymer (DES0-3) and PAM was better. Meanwhile, the flocculation effect was more optimistic in the strong alkali environment.

Systematic assessment of dredged sludge dewaterability improvement with different organic polymers based on analytic hierarchy process

Organic polymeric flocculants are commonly used in improving dredged sludge dewaterability, but less attention has been paid to residual water quality. In this paper, the effects of cationic etherified starch (CS) and poly-dimethyl diallyl ammonium chloride (PDDA) on dredged sludge dewatering efficiency and residual water quality of Baiyangdian lake were comprehensively investigated and evaluated by analytic hierarchy process (AHP). The results indicated that PDDA had stronger electrical effect and flocculation performance compared with CS, resulting in more efficient dewatering performance. PDDA can reduce the pollutants of discharged residual water, while CS significantly promoted the increase of NH4+-N and NO3–-N in the residual water. The increase of NH4+-N in the residual water of CS was due to the release of dredged sludge, while the increase of NO3–-N was introduced by CS leaching. AHP showed that PDDA performed better in flocculation treatment of dredged sludge than other organic polymers. This work provides a method for optimization of flocculation treatment for dredged sludge dewaterability.

Polyhydroxamic acid as an efficient metal chelator and flocculant for wastewater treatment

Hydroxamic acid containing organic polymeric flocculants were synthesized from three different commercially available polymeric flocculants, such as WAS590, Zetag 4100, and Zetag 4110. These three polymers are acrylamide and acrylic acid‐based copolymers with different molecular weights and anionic charge density. The conversion of the amide groups to hydroxamic acid groups in the polymers was carried out by the reaction with hydroxylamine at pH 14. The modified polymers were characterized for structure and composition by elemental analysis, FTIR, and NMR. The chelation activity of the modified polymers was determined toward iron (Fe3+) and copper (Cu2+). The flocculation activity of the non‐modified and modified polymers was evaluated toward produced water and scrubber water. The results showed that all the modified flocculants exhibit better chelation with Fe3+ and Cu2+. In addition, the modified polymers display improved flocculation effect on tested wastewater.

REMOVAL OF POLLUTANTS FROM DISPERSE BLACK DYE WASTEWATER BY MUCILAGE FROM DRAGON FRUIT PEEL

Apart from the large revenue, the textile industry in general and the dyeing process in particular are releasing huge amounts of wastewater that pollutes the environment and adversely affects human health. Treatment of this type of wastewater by coagulation and flocculation process requires lots of synthetic chemicals, implying a chemical hazard. Thus, this study evaluated the efficacy of mucilage extracted from the peel of dragon fruit (Hylocereus undatus) towards partly substitution of Poly Aluminium Chloride (PAC) used in coagulation and flocculation process for removal of turbidity and other pollutants from disperse black dye wastewater. The effects of pH, settling time, coagulant dosage and mucilage dosage on removal of turbidity, chemical oxygen demand (COD) and color, etc. were analyzed based on Jar-tests. The results showed that the addition of mucilage at 10 mg/L after PAC at 245 mg/L under optimal pH 7 and settling time 40 minutes removed turbidity up to 94.92%. The amount of PAC used was 3-10% less compared to total PAC needed for obtaining equal efficiency when used alone. The pollutant removal by mucilage was also comparable to Polyacrylamide (PAM) – a synthetically organic flocculants.