Preparation and characterization of oxidized wheat starch with hydrogen peroxide as an environmentally friendly oxidant

The starch oxidation involves oxidation of primary or secondary hydroxyl to carbonyl or carboxyl groups, whereas the number of these groups indicates the level of oxidation. Oxidized starch is used as surface sizing agent and coating binder in the paper industry, or as polymeric filler that increases the polymer degradability. The main objective of the presented study is to investigate the effects of various parameters on the oxidation process of the wheat starch, using dry method (Fig. 1). These parameters include oxidizer concentration, catalyst type (iron(II) sulphate, copper(II) sulphate and copper(II) citrate), presence of plasticizers/modifiers (ricinoleic acid, (R-(Z))-12- hydroxy-9-octadecenoic acid, RA) and diizopropyl tartarate ((dipropan-2-yl 2,3- dihydroxybutanedioate, DIPT) and reaction temperature (20 and 80 °C). The obtained results suggest that higher values of carbonyl and carboxyl groups lead to an increase of swelling capacity and solubility, while viscosity decreases, compared to the native wheat starch. The analysis of FTIR spectra, especially region of carbonyl/carboxyl groups absorption, reveals high impact of process parameters on the oxidation degree and band structure. The morphology of native and oxidized starches, investigated by the SEM method, shows that after oxidation the surface of the starch particles becomes smoother then for the native starch, with aggregation of small and large-sized granules

The effect of starch modification on the dye adsorption efficiency

Researches in the field of nanotechnology indicate the possibility of the development and application of bionanocomposites based on clay minerals and biopolymers as promising materials for the removal of pollutants from contaminated water. Therefore, this study is based on an examination of the effect of intercalation of starch or cationic starch with kaolin clay or diatomaceous earth on the adsorption properties of the obtained materials for the removal of anionic and cationic dyes from aqueous solutions. Structural characterization of the obtained materials was performed by Fourier transform infrared spectroscopy while the morphology of the samples was determined by Scanning electron microscopy. The removal efficiency of methyl orange and crystal violet dyes was tested in a batch system, while the dye concentration after the adsorption process was determined by UV-Vis spectrophotometry. It was found that modification of cationic starch with clay and diatomaceous earth improved the efficiency for removing crystal violet dye from an aqueous solution

A green adsorbent based on wheat starch for removal of selective organic pollutants from aqueous solutions

The objective of this study was to evaluate the adsorption efficiency of a cationic functionalized wheat starch, obtained with betaine hydrochloride and glycidyl trimethylammonium chloride by an environmentally friendly process without the use of organic solvents. Surface functional groups of samples were characterized by Fourier transform infrared spectroscopy, the morphology of the materials was examined using scanning electron microscopy, the nitrogen content was determined by elemental analysis, while UV-VIS spectroscopy and liquid chromatography-tandem mass spectrometry were used for adsorption investigation. The efficiency of obtained cationic starches to adsorb the anionic and cationic dyes, as well as selected pharmaceuticals and pesticides was investigated. Adsorption experiments were performed in a batch system to determine the effect of contact time, initial concentration, and pH of the solution on the removal efficiency of crystal violet dye, which was chosen as the model for the detailed study of adsorption. Pseudo-first and pseudosecond order models were used to examine the adsorption kinetic, while Langmuir and Freundlich isotherm models were applied to equilibrium adsorption data. The results showed that environmentally and economically acceptable adsorbents prepared in this study could be effective in removing the examined organic pollutants

Primena probiotika u proizvodnji edamskog sira

Traditionally, the most popular food delivery system for probiotic strains has been freshly fermented milk, as well as unfermented milk with cultures added. However, in the development of functional dairy products, cheese could offer certain advantages as a delivery system of live probiotics to the gastrointestinal tract, which is the target organ. Limited research on the incorporation of probiotic bacteria to different types of cheeses has shown that cheese is a viable carrier of these bacteria. However, in order to reach that target, viable cell count of 106 cfu/g for the probiotic in the final product may require some technological changes both in selection of the appropriate species and strains, and in supporting the cells to maintain their viability throughout storage before consumption. Our results have shown that this is possible in the case of Edam cheese which could be used as an adequate carrier of probiotic bacteria. The cultures of bifidobacteria, L. acidophilus, and DCC 240 used in a combination, demonstrated satisfactory survival during 120 days. In all cases, final numbers of viable cells were still above the levels suggested to produce their claimed health benefits.Paralelno sa povećanjem proizvodnje funkcionalne hrane povećava se i interes za proizvode koji sadrže probiotike. Neprikosnoveni lider u toj oblasti su sigurno fermentisana mleka ali i ostali prehrambeni proizvodi, među koje spadaju i sirevi, sve više privlače pažnju. Poznato je da postoje velike razlike među namirnicama u pogledu održavanja vijabilnosti ćelija probiotika i ste strane sirevi ispunjavaju čitav niz kriterijuma za neophodnih za preživljavanje probiotskih sojeva. Prema tome imajući u vidu pH sireva oksidoredukcioni potencijal, hemijski sastav, strukturu, puferska svojstva neosporno je da sirevi mogu biti dobri vektori za prenos probiotika. Iz tog razloga u ovom radu je primenjena starter kultura koja se sastojala od FD-DVS DCC-240 i probiotske kulture FD DVS Bifidobacterium lactis BB-12 i FD DVS Lactobacillus acidophilus La 5 u proizvodnji edamskog sira

Modification of cellulose-based waste materials for removal of methylene blue from wastewater

Different natural fibers and yarns (hemp, flax, and cotton), obtained as a waste from textile industry, were used for the removal of methylene blue from aqueous solution. In attempt to increase the adsorption efficiency, examined fibers and yarn were modified by sodium hydroxide solution. Characterization of examined samples was performed by scanning electron microscopy and Fourier transform infrared spectroscopy. It was shown that applied modification caused the differences in the distribution of hemicelluloses in the structure of examined fibers and fibers in yarn, inducing the changes in morphology and surface chemistry. These changes slightly improved the adsorption properties of hemp fibers, while in the case of cotton yarn modification had a negative effect on methylene blue adsorption. Nevertheless, adsorption efficiency of these waste fibers and yarns highly increase with the pH of the solution, enabling their utilization for methylene blue removal from wastewaters

Effect of alkali modification on adsorption efficiency of fly ash

As coal combustion in thermal power plants generates huge amounts of waste such as bottom ash and fly ash, there is a need to find new applications for these materials. One of the ways of its reuse is chemical or thermal modification of the ash in order to obtain new materials, which can be further used as adsorbents of various pollutants from water. The subject of this research was the alkali modification and alkali activation of fly ash in purpose to increase the adsorption capacity towards heavy metal ions. The success of modification process and characterization of the obtained materials was monitored by Fourier transform infrared spectroscopy, X-ray fluorescence spectroscopy and scanning electron microscopy. The concentration of zinc and cadmium ions after adsorption was determinated by atomic absorption spectroscopy. The kinetics of the adsorption process on the most efficient adsorbent were examined and the experimental data were compared with pseudo-first and pseudo-second order models. The achieved results show a positive effect of alkaline modification of fly ash on adsorption efficiency of both metals, while alkaline activation gives an exceptionally effective adsorbent in the case of zinc

Alkali-activated fly ash modified with polyethyleneimine as adsorbent for methylene blue removal from water

U cilju iskorišćenja industrijskog otpada, leteći pepeo je modifikovan radi dobijanjaefikasnih adsorbenata za uklanjanje metilensko plavog iz vode. Leteći pepeo je aktiviran uprisustvu NaOH na 550oC, i modifikovan različitim količinama polietilenimina.Karakterizacija polaznog i modifikovanih uzoraka izvršena je skenirajućom elektronskommikroskopijom i infracrvenom spektroskopijom sa Furijeovom transformacijom. Ispitan jeuticaj vremena kontakta i početne koncentracije adsorbata na adsorpcione kapacitetenemodifikovanog i modifikovanog letećeg pepela. Pokazano je da adsorpcionekarakteristike zavise od količine dodatog polietilenimina, kao i da adsorpcija prati brzinupseudo-drugog reda, a ravnotežni adsorpcioni podaci pokazuju bolje slaganje sa Frojndlihovom izotermom.In attempt to reuse industrial waste, fly ash was modified and converted into efficientadsorbent for the removal of methylene blue from water. Fly ash was activated in thepresence of NaOH at 550oC, and modified with different amounts of polyethyleneimine.The raw and modified samples were characterized by scanning electron microscopy andFourier transform infrared spectroscopy. The influence of contact time and initialadsorbate concentration on the adsorption capacity of unmodified and modified fly ash wasalso examined. It has been shown that the adsorption characteristics depend on the amountof polyethyleneimine added, that the adsorption follows a pseudo-second-order rate, andthe equilibrium adsorption data show better agreement with the Freundlich isotherm

Alkali modification of fly ash for adsorption of selected dyes

Fly ash (FA) is an industrial waste material generated during coal combustion in thermalpower plants. In order to reuse this kind of industrial waste, and at the same time to reduce itsquantity, fly ash was used as a cheap material for the preparation of efficient adsorbents for theremoval of selected dyes from water. For that purpose, different modification methods were used toobtain alkali-activated fly ash samples. The success of the modification process and characterizationof the unmodified and modified materials was monitored by Fourier transform infrared spectroscopy,and scanning electron microscopy/energy dispersive spectroscopy. The adsorption properties ofexamined samples were studied through the adsorption of methylene blue, crystal violet, alizarin red,and methyl orange. All samples showed the highest adsorption efficiency for crystal violet removal,while the sample modified with a combination of NaOH, Na2SiO3, and diatomaceous earth(FA/geopolymer) was the most efficient adsorbent for all selected dyes. Therefore, the influence ofinitial pH value and contact time on adsorption was examined for the adsorption of crystal violetonto FA/geopolymer. It was found that alkaline modification improves the adsorption characteristicsof fly ash making it a promising candidate to solve the problem of colored wastewater

Optimization of process removal of anionic dyes from aqueous media using cationic adsorbents based on starch

Tekstilna industrija spada u red industrija sa najvećom potrošnjom vode u svom proizvodnom procesu. Opšta karakteristika otpadnih voda iz tekstilne industrije je, pre svega, visok sadržaj organskih materija i visoka obojenost. Sa aspekta zaštite životne sredine, uslovi za ispuštanje otpadnih voda su sve strožiji, dok je primena ekološki i ekonomski prihvatljivih adsorbenata za tretman otpadnih voda veliki izazov današnjice. Upravo zbog toga, u okviru ovog rada ispitivana je mogućnost primene katjonskih adsorbenata na bazi prirodnog materijala skroba za uklanjanje metil oranž (MO) boje iz vodenih rastvora. Korišćena su dva derivata katjonskog skroba, skrob modifikovan sa glicidiltrimetilamonijum hloridom (CS-G) i skrob modifikovan sa betain hidrohloridom (CS-B). Karakterizacija funkcionalnih grupa na površini materijala izvršena je korišćenjem infracrvene spektroskopije sa Furijeovom transformacijom (FTIR), dok je morfologija materijala ispitana pomoću skenirajuće elektronske mikroskopije (SEM). Kako bi se utvrdili optimalni adsorpcioni uslovi ispitana je kinetika adsorpcije, adsorpcione izoterme, kao i uticaj pH vrednosti. Na osnovu dobijenih kapaciteta adsorpcije pri optimalnim uslovima, određene su efikasnosti uklanjanja MO iz vodenih medijuma. Takođe, ispitana je i adsorpcija drugih anjonskih i katjonskih boja. Ispitivani katjonski skrobovi su se pokazali kao efikasni adsorbenti za uklanjanje MO i drugih anjonskih (alizarin crveno S, ARS), ali i katjonskih (metilensko plavo, MB i brilijant zelena, BG) boja iz vodenih rastvora.The textile industry is one of the industries with the highest water consumption in its production process. The general characteristic of wastewater from the textile industry is, primarily, the high content of organic matters and high coloration. From the aspect of environmental protection, the conditions for wastewater discharge are becoming more stringent, while the application of environmentally and economically acceptable adsorbents for wastewater treatment is a great challenge today. For this reason, the possibility of using cationic adsorbents based on natural starch material to remove methyl orange (MO) from aqueous solutions was investigated. Two cationic starch derivatives were used, starch modified with glycidyltrimethylammonium chloride (CS-G) and starch modified with betaine hydrochloride (CS-B). Surface functional groups were characterized by Fourier transform infrared spectroscopy (FTIR), while the morphology of the material was examined using scanning electron microscopy (SEM). In order to determine the optimal reaction conditions, the kinetics of adsorption, adsorption isotherms, as well as the influence of pH values were examined. Based on the obtained adsorption capacities under optimal conditions, the efficiencies of MO removal from aqueous media were determined. The adsorption of other anionic and cationic dyes was also investigated. The tested cationic starches proved to be effective adsorbents for the removal of MO and other anionic (alizarin red S, ARS), but also cationic (methylene blue, MB and brilliant green, BG) dyes from aqueous solutions

Study of adsorption properties of cationic modified starch for phosphate removal from aqueous solutions

Cilj ovog rada bio je ispitivanje adsorpcionih svojstava materijala na bazi skroba za uklanjanje fosfora iz vodenih rastvora. U komunalnim i industrijskim otpadnim vodama fosfor je dosta prisutan u obliku rastvornih fosfata, pa je prečišćavanje otpadnih voda i uklanjanje fosfata od presudnog značaja za sprečavanje procesa eutrofikacije, odnosno pogoršanja kvaliteta voda usled bujanja biljnih vrsta, naročito algi i cijanobakterija. Zbog svoje jednostavnosti, ekonomičnosti i efikasnosti, adsorpcija postaje sve atraktivnija metoda za uklanjanje fosfata iz otpadnih voda. Kao adsorpcioni materijali korišćeni su katjonski skrobovi dobijeni katjonizacijom skroba sa glicidiltrimetilamonijum hloridom (CS-G) i betain hidrohloridom (CS-B). Adsorpciona ispitivanja su izvršena u šaržnom sistemu. Efikasnost adsorpcije određena je spektrofotometrijski, dok su apsorpcione krive iskorišćene za određivanje radne talasne dužine. Ispitana je kinetika procesa, adsorpcione izoterme, kao i uticaj pH vrednosti rastvora na kapacitet adsorpcije. Dobijeni rezultati su upoređeni sa modelima adsorpcionih izotermi (Langmuir i Freundlich) da bi se odredilo slaganje i dobile informacije o mehanizmu i tipu adsorpcionog procesa. Takođe, ispitan je i uticaj prisustva pojedinačnih anjona (sulfata, fluorida i nitrata) na efikasnost adsorpcije. Rezultati adsorpcionih ispitivanja su pokazali da se CS-G i CS-B mogu koristiti kao efikasni prirodni adsorbenti za uklanjanje jona fosfata iz vodenih rastvora.The aim of this study was to investigate the adsorption properties of starch-based materials for removing phosphorus from aqueous solutions. In municipal and industrial wastewater phosphorus is quite present in the form of soluble phosphates, so wastewater treatment and phosphate removal are crucial to prevent the process of eutrophication, i.e. deterioration of water quality due to the proliferation of plant species, especially algae and cyanobacteria. Due to its simplicity, economy, and efficiency, adsorption is becoming an increasingly significant method for removing phosphate from wastewater. Cationic starches obtained by cationization of starch with glycidyltrimethylammonium chloride (CS-G) and betaine hydrochloride (CS-B) were used as adsorption materials. Adsorption tests were performed in a batch system. The adsorption efficiency was determined spectrophotometrically, while the apsorption curves were used to determine the operating wavelength. The kinetics of the process, adsorption isotherms, as well as the influence of the pH value of the solution on the adsorption capacity were investigated. The obtained results were compared with models of adsorption isotherms (Langmuir and Freundlich) in order to determine the agreement and obtain information about the mechanism and type of adsorption process. The influence of the presence of individual anions (sulphate, fluoride, and nitrate) on the adsorption efficiency was also examined. The results of adsorption studies have shown that CS-G and CS-B can be used as effective natural adsorbents to remove phosphate ions from aqueous solutions