Colloidal Starch Research Articles

Synthesis of Green Brucite [NixMg1−x(OH)2] by Incorporation of Nickel Ions in the Periclase Phase (MgO) Applied as Pigments

Magnesium oxide is typically white and can be colorized with transition metal insertion by doping. We present the preparation of a green-colored hydroxide by the exchange of Mg2+ on the crystalline lattice with Ni2+ in MgO, using three nickel salts. MgOst was prepared by the colloidal starch suspension method, using cassava starch. The oxides and hydroxides, before and after, were characterized by X-ray diffraction (XRD), and show that a phase change occurs: a transition from periclase (MgO) to brucite (Mg(OH)2) due to the incorporation of nickel ions from different salts (acetate, chloride, and nitrate), resulting in the solid solution [NixMg1−x(OH)2]. The FTIR spectrum corroborates the crystallographic structure identified through XRD patterns, confirming the formation of a crystal structure resembling brucite. The new samples present a green color, indicative of the incorporation of the Ni2+ ions. The antimicrobial activity of products resulting from the doping of magnesium oxide with nickel and the precursor MgOst was assessed through the minimum inhibitory concentration (MIC) test. The evaluation included three bacterial strains: Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922), Salmonella gallinarum (ATCC 9184), and a yeast strain, Candida albicans (ATCC 10231). The obtained results were promising; the tested samples exhibited antimicrobial activity, with a MIC ranging from 0.312 to 0.625 μg.μL−1. The nickel compound, derived from the precursor chloride salt, demonstrated superior MIC activity. Notably, all tested samples displayed bactericidal activity against the S. aureus strain and exhibited a broad spectrum of inhibition, encompassing both Gram-positive and Gram-negative strains. Only the nickel compounds derived from precursors with acetate and nitrate anions demonstrated antimicrobial activity against C. albicans, exhibiting a fungistatic behavior. Based on the conducted studies, [NixMg1−x(OH)2] has emerged as a promising antimicrobial agent, suitable for applications requiring the delay or inhibition of bacterial growth.

Synthesis of Periclase Phase (MgO) from Colloidal Cassava Starch Suspension, Dual Application: Cr(III) Removal and Pigment Reuse

Synthesis of Periclase Phase (MgO) from Colloidal Cassava Starch Suspension, Dual Application: Cr(III) Removal and Pigment Reuse

Porous zincite prepared by the calcination of colloidal starch applied in the removal of dyes and its use as a hybrid pigment

A mesoporous zincite with a surface area of 10.34 m2 g−1, a pore volume of 0.030 cm3 g−1, and a pore radius of 1.98 nm was prepared using a colloidal dispersion of starch, calcined at 600 °C, and the resulting material was identified as the hexagonal wurtzite phase. The porous colorless zincite (PCZ) was used for the removal of textile dyes (blue and red) and removed 99.87% of blue dye, and 99.76% for red dye, owing to fast electrostatic interaction, leading to the formation of colored zincite as a hybrid pigment (HyPi). The HyPiblue and HyPired were combined with commercial white paint (10%, w/w), and its colorimetric characteristics (L*a*b*) were maintained with a decrease in the degree of reflectance in the visible-NIR region. After 48 h continuously exposed under the light to check the photoaging, the hybrid pigments dispersed in paint suggested high stabilities for the pigments. In this sense, the current study reveals a new strategy for the application of adsorbent containing toxic compost as a hybrid pigment ensuring the decrease of toxic elements in the environment.

In Ukrainian

For improve the quality of harvests, modern farms in many countries widely use fertilizers of mineral and natural origin. To mitigate the negative impact on the environment, they try to minimize the amount of mineral fertilizers applied to the soil by creating composite systems. In particular, powdered composite materials are known based on highly dispersed silica and microquantities of mineral fertilizers, which are applied to the surface of the seeds by dusting. The aim of this work was to develop a new generation of film stimulating coatings based on mixtures of hydrophobic AM-1-300 and hydrophilic A-300 silicas, mineral fertilizers and bioactive components. Mixtures of hydrophilic and hydrophobic silicas in the ratio 1:1 and 1:2 were used to obtain a pasty composite with the given stimulating properties; colloidal starch solution; medium salts of mineral acids, bioactive components “Humifriend” and fungicide “Fital”. Such composite systems were applied directly to the surface of sowing material, grains of wheat variety “Natalka” before sowing in sand and on filter paper, according to DSTU 4138-2002. During the study, the following parameters were measured: seed germination energy, germination and morphological characteristics of wheat germs, which consisted in measuring the length of the root and stem. It is shown that when editing certain amounts of bioactive components to the composition of stimulating pasty composites, it is possible to program the properties of future films and powders: to increase morphological characteristics, uniformity of germination and fungicidal characteristics of composites. It has been found that the presence of mineral fertilizers in pasty composites of silicas mixtures 1:1 and 1:2 has a positive effect on the uniform germination of wheat seeds in the sand and on the filter paper. Instead, the presence in the pastes of the active ingredients “Fital” and “Humifriend”, regardless of the environment where the seeds germinated, there is a significant slowdown in the growth of wheat germ in both environments. It has been found that an excess of hydrophilic silica in the pasty composite leads to the development on the surface of the grains of mycosis lesions, regardless of the germination environment. Therefore, stimulant pastes based on 1:2 silica mixtures must contain fungicides of mineral or biological origin.

Fabrication of three dimensional microfluidic system in poly(dimethylsiloxane) on piezoelectric substrate

A new method for prototype of a three dimensional (3 D) microfluidic device on piezoelectric substrate was presented. Wires were stick by colloidal starch, and dried in a thermotank for three dimensional channels mold. The mold was slightly placed in a groove with poly(dimethylsiloxane). After having been solidified, these wires were drawn off to form 3 D microchannels. Surface acoustic wave was used to driven sample droplet to the inlet of the microchannel in microfluidic device. Red fluid transportation in different microchannels was successfully demonstrated using the 3 D microfluidic device at 24.5 dBm signal power for verifying the function of the microfluidic device.

Interaction forces between colloidal starch and quartz and hematite particles in mineral flotation

In this study, we present theoretical and experimental data on the interaction forces between starch and particles of hematite and quartz as well as their implications for flotation and aggregation. The individual Hamaker constant for starch acting through vacuum, A11, was calculated, and its value, 6.27 × 10−20J, demonstrates the highly hydrophilic character of gelatinized starch. The Hamaker constants for quartz/water/starch and for hematite/water/starch, A132, were also calculated, and these values were 6.07 × 10−21J and 17.90 × 10−20J, respectively. It was confirmed that starch strongly adsorbs onto hematite, whereas on quartz, starch may adsorb onto only silicon surface sites. In fact, AFM images of quartz surfaces showed non-adsorbed areas or areas with a thin layer of starch that certainly do not interfere in subsequent adsorption by the collector (etheramine). The interaction energies between gelatinized starch and the hematite and quartz surfaces were estimated based on DLVO theory at pH 10.5 and a constant ionic strength (10−3 mol.L−1 NaCl). The repulsion electrostatic energy was higher for the quartz-starch system than for the interactions between hematite and starch. The calculated total energy of interaction between quartz and starch revealed that there is no possibility of aggregation for the individual colloids of starch and quartz particles. On the other hand, spontaneous adhesion between the colloids and hematite particles was confirmed by DLVO theory.

Colloidal Starch and Cellulose Nanocrystals Unite To Improve the Mechanical Properties of Paper: From Enhanced Coatings to Reinforced Nanocomposites

Emerging paper-based technologies encompassing lab-on-a-chip platforms, microfluidics, sensors, actuators, flexible electronics, and energy-storage devices, such as batteries, demand mechanically robust substrates. Current gold standards for paper and paper board reinforcement rely on petroleum-based binders and coatings, such as latex beads cured with melamine formaldehyde and urea formaldehyde resins, which have raised the red flag because of their environmental footprints. Here, we introduce an all-green reinforcing nanocomposite based on the ammonium zirconium carbonate (AZC)-mediated synergistic crosslinking of starch nanoparticles (biolatex) and a newly emerged type of nanocelluloses named anionic hairy cellulose nanocrystals. AZC, an environmentally friendly and cost-effective crosslinker, reacts with the hydroxyl groups of starch and cellulose nanocrystals, while the carboxylic acid groups of hairy nanocelluloses maintain the solution viscosity low, favoring industrial transportation, which may no...

Evolution of rheological properties of starch solutions obtained by mechanothermal and thermal methods

Regularities of the time variation of viscosity of colloidal starch solutions obtained by combined mechanical and thermal actions on biopolymer dispersions were studied.

Inhibition of methanogenic activity of starch-degrading granules by aromatic pollutants

The effects of nine common aromatic pollutants from chemical industry on the bioactivity of anaerobic granules were examined. The granules were obtained from an upflow anaerobic sludge blanket (UASB) reactor treating wastewater containing colloidal starch. The specific methanogenic activities (SMA) of granules were measured at 37°C in serum vials using 3000 mg/l of colloidal starch as substrate, plus individual pollutants at various concentrations. The toxicity was expressed by the IR50 and IC50 values, i.e. the toxicant/biomass ratio and concentration at which levels the granules exhibited only 50% of their original bioactivities. Results showed that in general the granules exhibited mild resistance to toxicity of aromatic pollutants, probably due to the granules' layered microstructure. The toxicities, which were dependent on the nature of chemical functional group, of the aromatic pollutants were in the following descending order: cresols > phenol > hydroxyphenols/phthalate > benzoate. There was only marginal difference between the toxicity of the steric isomers. For the seven phenolic pollutants, the more hydrophobic the functional group the higher the toxicity. The granules' resistance to toxicity suggested the plausibility of anaerobic treatment of wastewater from the chemical industry.

Inhibition of methanogenic activity of starch-degrading granules by aromatic pollutants

The effects of nine common aromatic pollutants from chemical industry on the bioactivity of anaerobic granules were examined. The granules were obtained from an uptlow anaerobic sludge blanket (UASB) reactor treating wastewater containing colloidal starch. The specific methanogenic activities (SMA) of granules were measured at 37°C in serum vials using 3000 mg/l of colloidal starch as substrate, plus individual pollutants at various concentrations. The toxicity was expressed by the IR50 and IC50 values, i.e. the toxicant/biomass ratio and concentration at which levels the granules exhibited only 50% of their original bioactivities. Results showed that in general the granules exhibited mild resistance to toxicity of aromatic pollutants, probably due to the granules' layered microstructure. The toxicities, which were dependent on the nature of chemical functional group, of the aromatic pollutants were in the following descending order: cresols>phenol>hydroxyphenols/phthalate>benzoate. There was only marginal difference between the toxicity of the steric isomers. For the seven phenolic pollutants, the more hydrophobic the functional group the higher the toxicity. The granules' resistance to toxicity suggested the plausibility of anaerobic treatment of wastewater from the chemical industry.

Washout kinetics of colloidal starch as a partial or full replacement for plasma exchange.

Colloidal starch has been used safely as a plasma expander and an erythrocyte sedimenting agent for over 25 years. However, there remains some concern in regard to the long term sequelae of the administration of large volumes of colloid starch such as would be administered if colloidal starch were used as a plasma replacement during serial plasma exchanges. We identified mathematical relations that allowed for the calculations of the theoretical circulating residual starch in a patient undergoing serial plasma exchanges and used it to model a variety of possible clinical scenarios. Following six one plasma volume exchanges, one would expect only 11, 13, 14, or 17% of the total infused starch to be remaining in the circulation. For example, in the case of a 4L exchange with full replacement, only the starch in 4.1 liters (4L x 6 exchanges x 17% = 4.1L) would be expected to remain in the circulation despite an infusion of 24 L (4L x 6 exchanges = 24L) of starch. The results suggest that relatively small amounts of starch would be expected to remain circulating relative to the large amounts infused following a series of plasma exchanges with partial or full starch replacement.

Hydrodynamic behaviour and oxygen transfer rate in a pilot plant fermenter: I. Influence of viscosity

AbstractThe effects of varying impeller speed, aeration rate and viscosity on mixing time, power consumption and oxygen transfer rate were studied in the pilot plant fermenter. The rheological behaviour of erythromycin fermentation broth was simulated by colloidal starch solutions at apparent viscosities of 0.02–0.20 Pa/s. The volumetric oxygen transfer rate coefficient was determined by the sulphite and static method. The experimental results showed that at low viscosities, up to of 0.02 Pa/s, the suitable range of impeller speed is 250–300 min−1 at aeration rate 0.6–0.8 VVM from the point of view of power input (2.6–2.8 kW/m3) and sufficient coefficient KLa (160–200 h−1). At viscosities higher than 0.02 Pa/s (with pseudoplastical character) the suitable range of impeller speed is 300–350 min−1 at the same aeration rate. Then the power input for mixing is 3.0–3.5 kW/m3 and the coefficient KLa ∼ 50 h−1.

Hydrodynamic behaviour and oxygen transfer rate in a pilot plant fermenter. I. Influence of viscosity

AbstractThe effects of varying impeller speed, aeration rate and viscosity on mixing time, power consumption and oxygen transfer rate were studied in the pilot plant fermenter. The rheological behaviour of erythromycin fermentation broth was simulated by colloidal starch solutions at apparent viscosities of 0.02–0.20 Pa/s. The volumetric oxygen transfer rate coefficient was determined by the sulphite and static method. The experimental results showed that at low viscosities, up to of 0.02 Pa/s, the suitable range of impeller speed is 250–300 min−1 at aeration rate 0.6–0.8 VVM from the point of view of power input (2.6–2.8 kW/m3) and sufficient coefficient KLa (160–200 h−1). At viscosities higher than 0.02 Pa/s (with pseudoplastical character) the suitable range of impeller speed is 300–350 min−1 at the same aeration rate. Then the power input for mixing is 3.0–3.5 kW/m3 and the coefficient KLa ∼ 50 h−1.

Inhibiting Influence of Colloidal Starch, Inulin, and Agar on the Stimulation of Aspergillus niger by Zinc Sulphate

Inhibiting Influence of Colloidal Starch, Inulin, and Agar on the Stimulation of Aspergillus niger by Zinc Sulphate