Amphoteric Starch Research Articles

The novel chitosan-amphoteric starch dual flocculants for enhanced removal of Microcystis aeruginosa and algal organic matter

A novel flocculation strategy for simultaneously removing Microcystis aeruginosa and algal organic matter (AOM) was proposed using chitosan-amphoteric starch (C-A) dual flocculants in an efficient, cost-effective and ecologically friendly way, providing new insights for harmful algal blooms (HABs) control. A dual-functional starch-based flocculant, amphoteric starch (AS) with high anion degree of substitution (DSA) and cation degree of substitution (DSC), was prepared using a cationic moiety of 3-chloro-2-hydroxypropyltrimethylammonium chloride (CTA) coupled with an anion moiety of chloroacetic acid onto the backbone of starch simultaneously. In combination of the results of FTIR, XPS, 1H NMR, 13C NMR, GPC, EA, TGA and SEM, it was evidenced that the successfully synthesized AS with excellent structural characteristics contributed to the enhanced flocculation of M. aeruginosa. Furthermore, the novel C-A dual flocculants could achieve not only the removal of >99.3 % of M. aeruginosa, but also the efficacious flocculation of algal organic matter (AOM) at optimal concentration of (0.8:24) mg/L, within a wide pH range of 3–11. The analysis of zeta potential and cellular morphology revealed that the dual effects of both enhanced charge neutralization and notable netting-bridging played a vital role in efficient M. aeruginosa removal.

Co-utilization of lake sediment and blue-green algae for porous lightweight aggregate (ceramsite) production

Lake sediment and algal sludge with large output posed significant environmental risks. In this work, an idea of co-utilization of both solid wastes for the production of ceramsite (a sort of porous lightweight aggregates as building materials) was proposed and validated for the first time. The treatment process contained a dewatering step by a flocculation-pressure filtration method, and a sintered ceramsite preparation step. Effects of flocculant type and dosage on the dewatering performance were studied in the first step. An environmental-friendly amphoteric starch flocculant with a dosage of 12 mg/(g dried sample) was found to achieve the best dewatering performance. Effects of raw material mass ratio, sintering temperature and time in the second step were investigated. Under the optimal conditions (60 wt% of dewatered sediment; 20 wt% of dewatered algal sludge; 20 wt% of additives (fly ash: calcium oxide: kaolin = 2:1:2); sintering temperature: 1100 °C; time: 35 min), the obtained ceramsite met the Chinese National Standard as a qualified building material, with reliable environmental safety according to the leaching results for both heavy metals and microcystins. Both environmental and economic benefits of the proposed treatment were assessed. The process completely followed the rules of “reduction, harmlessness and resource utilization” for solid waste treatment and disposal; Meanwhile, the profit of the proposed ceramsite production could be more than 2.3 US dollar/m3. The co-utilization method in this work acted as a good example for the comprehensive management of solid wastes in water-rich areas.

Application of a modified biological flocculant in total nitrogen treatment of leather wastewater.

Leather wastewater harms the ecological environment and human health. In this study, a modified bio-flocculant was prepared to facilitate treatment of leather wastewater. A bio-flocculant produced by Bacillus cereus was combined with amphoteric starch and modified using a cerium ammonium nitrate initiator. Single factor optimization and orthogonal optimization were used to determine the optimal preparation conditions as follows: amphoteric starch-to-flocculant ratio = 22:30; reaction temperature = 64 °C; initiator dosage = 2.00%; reaction time = 15 min; stirring speed = 600 rpm; and flocculation system pH = 8.0. At a dosage of 1 g/L added to simulated leather industry wastewater, the flocculation efficiency (98.17%) and the total nitrogen removal efficiency (100.00%) of modified bio-flocculant was superior to that achieved by 1 g/L of unmodified bio-flocculant (72.16% and 50.00%, respectively), amphoteric starch (8.50% and 0.00%) and polyacrylamide (95.55% and 75.00%). Analysis of natural and flocculated precipitates in the wastewater showed that the modified bio-flocculant significantly changed several characteristics of the flocculated particles; in addition, it promoted the removal of nitrogenous substances in the process of denitrification. These changes helped explain the material's flocculating ability. The results confirmed that the modified bio-flocculant was an effective additive for treating leather wastewater.

Amphoteric starch-based bicomponent modified soil for mitigation of harmful algal blooms (HABs) with broad salinity tolerance: Flocculation, algal regrowth, and ecological safety

The treatment of harmful algal blooms (HABs) by in-situ flocculation is an emerging technology capable of efficiently removing HABs from natural waters. However, differences in salinity, pH and algal species in freshwaters and seawaters can influence the flocculation treatment. In this study, we developed a bicomponent modified soil using amphoteric starch (AS) and poly-aluminium chloride (PAC) in order to effectively flocculate microalgae under broad salinity conditions. Specifically, the impacts of water salinity (0–3.3%), pH (3–11), and algal species (Microcystis aeruginosa and marine Chlorella sp.) were investigated in order to evaluate efficiency, dosage and mechanisms of algae flocculation. The results showed that AS-PAC modified soils possessed excellent resistance to salinity change due to the anti-polyelectrolyte effect of AS, which contributed to 99.9% removal efficiency of M. aeruginosa in fresh and saline waters, and Chlorella sp. in marine water, respectively. The dosage of the flocculant modifier was only 10–20% of that of another proven modifier (i.e. Moringa oleifera), which substantially reduced the material cost. The high salinity tolerance of algal flocculation by the AS-PAC modified soil was attributed to the synergistic processes of charge neutralization and netting-bridging. Thus, this study has developed a universal flocculant and revealed fundamental mechanisms for the mitigation of HABs under broad salinity conditions.

Amphoteric starch derivatives as reusable flocculant for heavy-metal removal.

A pH-responsive amphoteric starch derivative (PRAS) bearing dual functional groups (amino and carboxyl groups) was prepared through etherification of starch with 2-chloro-4,6-diglycino-[1,3,5]-triazine. PRAS exhibits a reversible pH-response property in aqueous solution. The attractive property of PRAS is that it could be used as an effective flocculant for heavy metal-ion (e.g. Cu(ii) and Zn(ii)) removal from wastewater by changing pH. The transition of hydrophobicity–hydrophilicity would produce shrinkage of the polymer matrix, facilitating the release of heavy-metal ions from the saturated flocculant. As an ideal flocculant PRAS displayed outstanding stability and reproducibility, whose remove rate for Cu(ii) and Zn(ii) remained at 93% and 91% after three flocculation/regeneration cycles.

Removal of both cationic and anionic contaminants by amphoteric starch

A novel amphoteric starch incorporating quaternary ammonium and phosphate groups was applied to investigate the efficiency and mechanism of cationic and anionic contaminant treatment. Its flocculation abilities for kaolin suspension and copper-containing wastewater were evaluated by turbidity reduction and copper removal efficiency, respectively. And the kinetics of formation, breakage and subsequent re-formation of aggregates were monitored using a Photometric Dispersion Analyzer (PDA) and characterized by flocculation index (FI). The results showed that amphoteric starch possessed the advantages of being lower-dosages-consuming and being stronger in shear resistance than cationic starch, and exhibited a good flocculation efficiency over a wide pH range from 3.0 to 11.0.

Efficacy of carbohydrate polymers in filler preflocculation for use in papermaking

Preflocculation of inorganic fillers added to the paper could improve the inter-fiber bonding and enhance paper strength. Selection of a suitable flocculant and flocculating conditions for improved efficacy of the process is highly desired. The flocculating process conditions such as stirring speed, concentration of filler suspension and retention time were optimized through image analysis of the filler flocs when using cationic starch as flocculant. Two carbohydrate polymers, cationic and amphoteric starch, were used at 0.1%, 0.4% and 0.8% doses for the preflocculation of talc filler under optimized conditions. The colloidal charge and particle size distribution of the native and preflocculated fillers were analyzed. The native and preflocculated fillers were added to bleached mixed hardwood kraft pulp for preparing laboratory handsheets of 60g/m2 targeting varying ash levels of 15–24%. Various paper properties such as tensile, burst, tear indices, light scattering coefficient, Cobb60 and contact angle were analyzed for the native as well as preflocculated fillers. The median particle size of native filler was 6.0μm which on preflocculation using 0.8% dosage of cationic and amphoteric starch increased to 12.0μm and 14.8μm i.e. 100% and 146% increase in particle size, respectively. The preflocculated filler increased the physical and hydrophobic properties of the sheets as compared with the native filler. The increase in tensile index was about 20% when filler was preflocculated using 0.8% dose of amphoteric starch.

Role of particle size and preflocculation of talc in improvement of paper properties

Mineral fillers are added during papermaking to improve the optical and printing properties of paper and decrease energy costs. Filler loading using conventional approaches has some disadvantages, such as reduction in paper strength. The finer filler, the more the strength loss. Several methods and materials have been reported to overcome or alleviate the same, but with higher costs. Our approach provides an economically viable solution to the problem, using conventional papermaking materials. Talc filler of different particle sizes, preflocculated using different doses of cooked amphoteric starch, were used for papermaking. Relatively higher filler retention, paper strength, and hydrophobicity of paper were obtained with preflocculated talc compared to native talc. The optical properties of paper were unchanged on the loading of similar talc after preflocculation. The preflocculated talc of finer particle size provided higher opacity at similar ash, as well as paper strength, than the native talc of coarser size.

Use of Poly-Lactic Acid (PLA) to Enhance Properties of Paper Based on Recycled Pulp

Nowadays, recycled paper is broadly used due to environmental reasons. Furthermore, the addition of starch as a dry strength additive improves the properties of recycled paper. Poly-Lactic Acid (PLA), a product from bio-refinery process, has recently been shown to act as a promising strength additive that could be used in combination with starch to further improve the strength of paper. In this study, the use of PLA of three molecular weights (MW) in combination with four different starches was investigated. Three recycled pulps from different origins, with the kappa number of 27.9 to 66 were used. Paper handsheets were made, and selected paper properties were tested. The results indicate that handsheets properties were influenced by the MW of PLAs, the type of starch used, and the lignin content of the pulp. The paper handsheets made from lignin-rich pulp (pulp A, kappa number 66), combined with 0.1% medium MW PLA (PLA_1) and 0.9% cationic starch containing 0.43% N gave the highest improvement for tensile strength, wet tensile strength, air and water resistance. This result verifies that a higher kappa number pulp has better attraction to the hydrophobic PLA. Moreover, the higher charge cationic starch led to higher tensile strength due to the increase of affinity to the anionic fiber surface. Interestingly, results show that amphoteric starch is a promising substitute for high cationic charge starch when combined with the medium MW PLA to improve tensile strength of paper. This study demonstrated that a starch-PLA blend represents a promising approach in improving properties of recycled paper.

Absorption of Hg (II) Form Aqueous Solution onto Double Crosslinked Amphoteric Cassava Starch Resin

Sodium polyphosphate-crosslinked starch was synthesized by using cassava starch and sodium polyphosphate as main material and crosslinked agent individually. On above basis, double crosslinked amphoteric cassava starch resin was synthesized through three steps of reactions, which included the inner-crosslinked reaction of starch with N,N'-methylene bisacrylamide, the grafted reaction of the obtained copolymer with dimethyl diallyl ammonium chloride (DMDAAC) and the grafted reaction of the obtained copolymer with acrylic acid. The product was characterized by scanning electron microscopy (SEM). The results indicate that the cassava starch was modified successfully. Adsorption behavior of Hg2+ was studied in the condition of different adsorption time, and found that the removal rate and the adsorption capacity of Hg2+ reached up to 95.98% and 191.97 mg/g respectively.

Preparation of Amphoteric Polyacrylamide-Grafted Starch Flocculant and its Application

A polyacrylamide-grafted starch (St-g-AM-DMC-AMPS) flocculant for the coal slurry wastewater was prepared by using corn starch (St), acrylamide (AM), methyl acryloyloxyethy trimethyl ammonium chloride (DMC) as cationic monomer, 2-acrylamido-2-methyl acrylate sulfonic acid (AMPS) as anionic monomer through solution polymerization. The structure of the synthesized St-g-AM-DMC-AMPS was characterized by FT-IR and TG. The effects of initiator concentration, reaction temperature and monomer concentration on percentage of grafting and the grafting efficiency were investigated. The results showed that the optimal conditions of the polymerization are that the ratio of substrate and monomer is 3:7, the radio of ammonium persulfate is 0.15%, reaction time is 4h and reaction temperature is 50°C. The additional dosage of St-g-AM-DMC-AMPS is varying between 12mg/L and 20 mg/L to obtain better flocculation capability than PAM.

Synthesis of Double Crosslinked Amphoteric Cassava Starch Resin and Performance of Absorbing Cu (II)

Sodium polyphosphate-crosslinked starch was synthesized by using cassava starch and sodium polyphosphate as main material and crosslinked agent individually. On above basis, double crosslinked amphoteric cassava starch resin was synthesized by N,N'-methylene bisacrylamide as inner-crosslinked agent, dimethyl diallyl ammonium chloride (DMDAAC) and acrylic acid as amphoteric grafted monomer. The product was characterized by infrared spectrum (FTIR). The results indicate that the cassava starch was modified successfully, and the final product was double crosslinked amphoteric cassava starch resin. Adsorption behavior of Cu2+ was studied in the condition of different adsorption time, and found that the removal rate and the adsorption capacity of Cu2+ reached up to 98.3% and 196.6 mg/g respectively.

Structural characteristics and flocculation properties of amphoteric starch

Starch ampholytes (AmS) – cationic starch succinates – with the degree of substitution according to cationic groups of 0.29 or 0.36 and the degree of substitution according to anionic groups from 0.11 to 0.34 were prepared by succinylation of precationized starch. FT-IR spectra confirmed the incorporation of carboxylic groups into the backbone of cationic starch. Scanning electron microscopy was used for evaluation of the granular structure and surface morphology of modified polysaccharides. The decrease in accessibility of cationic quaternary ammonium groups in AmS was detected by means of polyelectrolyte titration. Colloidal dispersions of AmS were verified in the flocculation of kaolin suspensions and the sedimentation of wastewater sludge. Their flocculation performance was studied in connection with ξ-potential measurements and compared with that of cationic starch. The main advantage of AmS application is broadening of the flocculation window. The mechanism of flocculation by starch ampholytes has been proposed.

Structure of Phosphate Amphoteric Cassava Starch and its Reinforcing Effect on Secondary Fiber

In the present work, a series of the phosphate amphoteric cassava starch was synthesized by a two-step semi-dry process with 3-chloro-2-hydroxypropyltrimethyl ammonium chloride (CTA) as the cationic reagent and phosphate mixture as the anionic reagent. The structure of the amphoteric starch was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The reinforcing effects of the amphoteric starch on the secondary fiber were also studied. The results indicated that the reaction occurred not only on the surface but also in the interior of starch granule, not only in the amorphous region, but also in the crystalline region. All the amphoteric starch showed reinforcing effect on the secondary fiber. The No. 5 sample showed better reinforcing effects on paper strength due to its higher total degree of substitution (0.095), proper DSA/DSC ratio (DSC=0.067, DSA=0.028) and interior modification of the starch granule. Compared with the control sample, the secondary fiber paper with 1.0 wt% (relative to dried pulp) of No.5 phosphate amphoteric starch showed 25.6%, 21.4% and 29.4% increases in tensile index, tearing index, and burst index, respectively.

Synthesis, flocculation and adsorption performance of amphoteric starch

A novel amphoteric copolymer flocculant was synthesized by incorporating a cationic moiety 2,3-epoxypropyl trimethyl ammonium chloride (GTA) and an anion moiety phosphate onto the backbone of starch with microwave radiation. The synthesized starch copolymer was characterized and examined by FTIR, 1H NMR spectroscopy, scanning electron microscopy (SEM), molecular mass and polydispersity, swelling power and solubility index. Flocculation performance was evaluated in 50mg/L methyl violet solution. It has been found that these flocculation characteristics mainly depended on the charge neutralization, followed by the interchain bridging of the amphoteric copolymer. Also, adsorption to Pb (II) solution was investigated by jar test. The results showed that the adsorption capacity of amphoteric copolymer correlated with pH value, adsorption time and initial Pb (II) concentration.

Comparative study on sizing properties of amphoteric starch and phosphorylated starch for warp sizing

By varying the ratios of N-(3-chloro-2-hydroxypropl) trimethylammonium chloride and orthophosphate to starch, a series of amphoteric starch with different degree of substitution (DS) were prepared for evaluating sizing effect of amphoteric starch for cotton warps. The amphoteric starch contained quaternary ammonium and phosphate groups simultaneously, and was set to electric neutrality by varying relative quantity of anionic and cationic groups in order to prevent adverse effects of negative and positive charges. The influence of amphoteric modification of starch on the adhesion to cotton fibers was assessed by measuring tensile strength and work-to-break of slightly sized cotton roving and comparing the adhesion of amphoteric starch with those of phosphorylated one. Comparison on mechanical performances of amphoteric starch film over phosphorylated one was evaluated in terms of tensile strength, breaking extension and wear loss of starch film. The properties such as increase in tensile strength, loss in elasticity, abrasion resistance, and hairiness of cotton yarns sized with amphoteric starch were evaluated through control tests by the comparison with those of phosphorylated one. When zeta potential of amphoteric starch was set close to zero, the adhesion increased and the properties of sized yarns enhanced as the modification level increased. The amphoteric starch was evidently superior to phosphorylated one in improving the quality of sized cotton yarns. The amphoteric starch with neutral zeta potential and DS levels of 0.02–0.03 for quaternary ammonium groups and phosphate ones, respectively, could be applied to size cotton warp yarns for the improvement of yarn quality.

Effect of enzymatic pretreatment on the synthesis and properties of phosphorylated amphoteric starch

► Phosphorylated amphoteric starch was prepared from enzyme-modified starch. ► The optimum reaction parameters were studied using response surface methodology. ► Enzymatic pretreatment improved the reaction processes significantly. ► The pasting stability of amphoteric starch from enzyme-pretreated tapioca starch was improved. Phosphorylated amphoteric starch was prepared from enzyme-modified tapioca starch in the aqueous alcoholic–alkaline medium. Optimization of the reaction parameters for maximum degree of substitution (DS) of phosphorylated amphoteric starch were carried out using response surface methodology (RSM). Optimum modification conditions were shown as following: NaOH concentration 3.71 g/100 g starch (dry basis), CHPTAC concentration 6.34 mL/100 g starch (dry basis), STP concentration 6.13 g/100 g starch (dry basis), water/ethanol ratio 1.16, reaction temperature 50 °C, reaction time 3 h, and the starch concentration 30%. Under the optimal condition, the maximum anion degree of substitution (DS A ) and cation degree of substitution (DS C ) were 0.0274 and 0.0408, respectively. Compared with the DS of the amphoteric starch prepared from native tapioca starch (NPTAS), the DS of the amphoteric starch from enzyme-pretreated tapioca starch (EPTAS) was higher at the same reaction conditions, suggesting enzymatic pretreatment improved the reaction processes significantly. Scanning electron microscopy and X-ray diffraction data showed that the granular shape and crystalline structure of EPTAS did not change. Compared with NPTAS, the pasting stability of EPTAS with the same DS was also significantly improved.

Synthesis of a Novel Double Crosslinking Amphoteric Cassava Starch

The grafted copolymerization of dimethyldiallylammoniumchloride (DMDAAC) and N,N'-methylene bisacrylamide onto cassava starch was investigated with water as solvent and ammonium persulfate-sodium sulfite as redox initiator. In above conditions, double crosslinking amphoteric cassava starch was synthetized by using sodium hydroxide as catalyst, epichlorohydrin as crosslinking agent and chloroacetic acid as etherification agent. The DS and DC could reach to 0.108 and 0.391 respectively under the following conditions: m(AGU) : m(DMDAAC)=1:1.5, the initiator mass fraction 3.5% (vs. dry starch), grafted polymerization temperature 45°C and time for 5 h, etherification temperature 50°C and time for 5 h, n(AUG):n(ClCH2COOH)=1:1 and n(AUG):n(NaOH)=1:1.5. The product was characterized by infrared spectrum (FTIR), scanning electron microscopy (SEM) and X-ray diffraction spectrum (XRD). The results indicate that the cassava starch is modified successfully, and the final product is a novel double crosslinking amphoteric cassava starch.

Study on AKD Improves Regenerated Paper Fiber Properties

AKD is an important internal size for paper pulp fiber. With recycled economy development, regenerated paper fiber becomes an important resource. In this paper, AKD is used as a modification aid by internal sizing method. It shows that the change of the dosage of AKD influences regenerated paper fiber Cobb value, but has no influence to paper surface strength. The proper pH value is from 7 to 9. The temperature has no influence to regenerated paper fiber Cobb value and paper surface strength. Appropriate modified starch is good for AKD modification fiber and increase of the surface strength of paper made from modified fiber by AKD. Amphoteric starch is better than cationic starch. Other added substances such as PEI, MPEI and PAE can improve the modification of paper fiber modified by AKD. So the adsorption of modified paper fiber decrease and the surface strength of paper modified fiber increase.

Study on Structure of Amphoteric Starch and Its Reinforcing Effect on Secondary Fiber

In the presented work, a series of the phosphate amphoteric cassava starch were synthesized by a two-step semi-dry process with 3-chloro-2-hydroxypropyltrimethyl ammonium chloride (CTA) as the cationic reagent and phosphate mixture as the anionic reagent. The structure of the amphoteric starch was characterized by FTIR and XRD. The reinforcing effects of the amphoteric starch on the secondary fiber were also studied. The results indicated that the reaction occurred not only in the amorphous region, but also in its crystalline region. When the cationic starch reacted with different amount of phosphates, the degree of cation substitution (DSc) of products was decreased with the dosage of the phosphates. When cationic starch with different DSc reacted with the same amount of phosphates, the degree of anion substitution (DSa) of products was decreased with the DSc. All the amphoteric starch showed reinforcing effect on the secondary fiber. The No. 7 sample showed better reinforcing effects on paper strength due to its higher total degree of substitution (0.095), proper DSa/DSc ratio (DSc = 0.067, DSa = 0.028) and interior modification of the starch granule. Compared with the control sample, the secondary fiber paper with 1.0 wt % (relative to dried pulp) of 7# modified starch showed 23.5%, 20.3% and 29.4% increases in tensile index, tearing index, and burst index, respectively.