Biosorption of copper(II) and chromium(VI) by modified tea fungus

The tea fungus was found to have good adsorption capacities for heavy metal ions. In this work it was treated with HCl or NaOH at 20°C or 100°C, with the aim to improve its adsorption ability. The sorption of Cu(II) and Cr(VI) ions from aqueous solutions by raw and treated tea fungus was investigated in the batch mode. The largest quantity of adsorbed Cu(II), of about 55 mg/g, was achieved by tea fungus modified with NaOH at 100°C. For Cr(VI), the largest quantity of adsorbed anions, of about 58 mg/g, was achieved by the adsorbent modified with NaOH at 20°C. It was shown that acid modification of tea fungus biomass was not effective. [Projekat Ministarstva nauke Republike Srbije, br. III 43005 i br. TR 31002

Characterization and utilization of the permeate and retentate obtained after “dead-end” ultrafiltration

In the recent years, with the increase in bioethanol production, the increasing amounts of distillery wastewater are generated. Such wastewater (stillage) is one of the most polluted waste product of the food and beverage industries. The present study evaluates the treatment of distillery wastewater by ultrafiltration (UF), in order to reduce its pollution and evaluate the composition of the permeate and retentate. Polyethersulfone ultrafiltration membrane with molecular weight cut-off (MWCO) 30000 Da, was used for the experiments. The UF was carried out in dead-end mode. The results of the analyses of the permeate and retentate obtained after ultrafiltration were considered as well as different ways for their further utilization. The pollutant level in the permeate was decreased significantly in comparison to the raw stillage, and suspended solids were completely removed from the stillage. [Projekat Ministarstva nauke Republike Srbije, br. TR 31002

Microfiltration of distillery stillage: Influence of membrane pore size

Stillage is one of the most polluted waste products of the food industry. Beside large volume, the stillage contains high amount of suspended solids, high values of chemical oxygen demand and biological oxygen demand, so it should not be discharged in the nature before previous purification. In this work, three ceramic membranes for microfiltration with different pore sizes were tested for stillage purification in order to find the most suitable membrane for the filtration process. Ceramic membranes with a nominal pore size of 200 nm, 450 nm and 800 nm were used for filtration. The influence of pore size on permeate flux and removal efficiency was investigated. A membrane with the pore size of 200 nm showed the best filtration performance so it was chosen for the microfiltration process

Ispitivanje koagulacione aktivnosti prirodnih koagulanata ekstrahovanih iz različitih sorti pasulja

Coagulation and flocculation by adding chemicals are the methods that are usually used for removal of water turbidity. This study is concerned with the coagulation activity of extracts of various strains of bean. The aim was to ascertain if bean varieties influence coagulation activity. Active components were extracted from 1 g of ground sample with 100 ml distilled water. Contents of dry matter and nitrogen were specified in the solid samples, and the content of soluble nitrogen was determined in the extracts. These data were used to calculate the efficiency of extraction of nitrogen-containing compounds. The coagulation activity was assessed by jar test using synthetic turbid water, of the initial pH 9 and turbidity 35 NTU. The jar test was carried out by adding different amounts of extracts to model water, and stirring the content. After sedimentation for 1 h, residual turbidity was determined by turbidimeter and coagulation activity was calculated. The increment of organic matter concentration after the coagulation was also determined. These experiments confirmed that extracts of all investigated strains of bean could be used successfully as natural coagulants.Koagulacija i flokulacija predstavljaju najčešće primenjivane metode za bistrenje vode, i uglavnom se izvode dodatkom hemijskih koagulanata. U ovom radu je ispitivana koagulaciona aktivnost ekstrakata dobijenih iz semena različitih sorti pasulja, a s ciljem da se utvrdi mogućnost njihove primene kao prirodnih koagulanata za uklanjanje mutnoće vode, i da se utvrdi uticaj sorte pasulja na koagulacionu aktivnost. Ekstrakcija aktivnih komponenti je izvedena sa 100 ml destilovane vode iz 1 g samlevenog uzorka. U čvrstim uzorcima je određen sadržaj suve materije i azota, a u ekstraktima sadržaj rastvorljivog azota, na osnovu čega je određena efikasnost ekstrakcije jedinjenja sa azotom. Za određivanje koagulacione aktivnosti ekstrakata izveden je džar-test, dodavanjem različitih doza ekstrakata model vodi, čiji je pH 9 i početna mutnoća 35 NTU. Nakon mešanja u određenom vremenskom intervalu, čaše su ostavljene da se njihov sadržaj istaloži, a zatim je u bistrom delu određivana mutnoća, i preko nje koagulaciona aktivnost. Takođe je utvrđen doprinos svakog od ekstrakata porastu sadržaja organskih materija u vodi nakon njenog bistrenja u odnosu na slepu probu, a preko permanganatnog broja. Ovim eksperimentima potvrđeno je da se ekstrakti svih ispitivanih sorti pasulja mogu uspešno primeniti kao prirodni koagulanti

Diversity of maize (zea mays l.) Landraces in eastern Serbia: morphological and storage protein characterization

Ten maize accessions (labelled as PF-ZM plus number) from Eastern Serbia were characterized by means of morphological and storage protein analysis. Estimation of 20 morphological traits was based on the IBP-GR Descriptors for maize. Zein composition was determined by the SDS gel electrophoresis. Variation of morphological characteristics among populations ranged from 4% for kernel width to 28% for kernel length. Accessions with the highest values of morphological traits were identified: PF-ZM 4 for ear diameter and kernel length, PF-ZM 5 for number of leaves and diameters of cob and rachis, PF-ZM 12 for leaf width and kernel thickness, PF-ZM 18 for number of kernels per row, PF-ZM 34 for number of ears per plant, venation index, number of rows per ear, and diameter of ear basis, and finally PF-ZM 37 for plant height, leaf length, and ear length. The gel electrophoresis showed the presence of five different fractions of zein proteins, which were classified as alpha-zeins and gamma-zeins. The alpha-zeins comprised on average 64 percent of the total registered zeins. Molecular weights of alpha-zein fractions identified on the gels were 17, 18, 21 and 24 kDa, and the only fraction identified as gamma-zein was 27 kDa. The assessment of morphological / productive traits of landraces, together with molecular markers, could represent a prerequisite for their protection. At the same time, such information could be of importance for both scientists and breeders

Secondary pollution of water during the biosorption of heavy metal ions by pristine and sugar beet shreds from bioethanol production

When biomaterials are used as adsorbents, some compounds present in their structure can be extracted and cause secondary pollution of the treated water. Depending on the type and amount of the secondary pollution, some materials can be unacceptable as adsorbents despite of their good adsorption capacity. Although, it is not a newly discovered phenomenon and it is recognized as a problem, leaching from adsorbents is neglected. The aim of our study is to investigate the secondary pollution of the water during the biosorption of heavy metal ions by pristine and modified sugar beet shreds from bioethanol production. The presence of different elements in the mentioned adsorbents, secondary pollution of the water during the adsorption of heavy metal ions and amount of reducing sugars in the water treated by pristine sugar beet shreds were characterized by the SEM-EDS method, the amount of the leached inorganic and organic matter from the adsorbents (atomic absorption spectroscopy and permanganate index) and Bertrand's method, respectively. Furthermore, the obtained results were compared to the available literature data. Our results showed that according to the valid regulations of emission limit values of the polluting substances in the water and adsorption capacity, the investigated adsorbents have a great potential as biosorbents for practical treatment of wastewaters which contain high concentrations of heavy metal ions. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III 43005

Flux intensification during microfiltration of distillery stillage using a kenics static mixer

The present work studies the effect of operating parameters (pH, feed flow rate, and transmembrane pressure) on microfiltration of distillery stillage. Experiments were conducted in the presence of a Kenics static mixer as a turbulence promoter, and its influence on the flux improvement and specific energy consumption was examined. Response surface methodology was used to investigate the effect of selected factors on microfiltration performances. The results showed that response surface methodology is an appropriate model for mathematical presentation of the process. It was found that the use of a static mixer is justified at the feed flow rates higher than 100 L/h. In contrast, the use of a static mixer at low values of feed flow rate and transmembrane pressure has no justification from an economic point of view. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR 31002

Comparison of the generalized and preset-order kinetic equations for description of biosorption data

Time course of adsorption of the different pollutants from water is the basis in the testing of an adsorbent. Over the years, several kinetics models have been proposed. Nevertheless, pseudo-first-order and pseudo-second-order kinetic models are by far the most used in the testing. Since various biological materials have complex composition, it is assumed that the adsorption kinetics on such materials, named biosorbents, can not be described sufficiently well by these two models. In this paper, both generalized and preset order kinetic equations were applied on the results of copper and chromium ions adsorption onto spent brewer’s grain. The biosorption of copper ions corresponds the best to the 2.5, and biosorption of chromium ions to the 4.9 reaction order. The analyses of the kinetic tests results on different biosorbents conducted by other authors indicate that the determination of the reaction order should be obtained by generalized kinetic model. It was also established that the f value (relative goodness of curve fitting) was better for the prediction which equations is better, than the R value (correlation coefficient). [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III43005

Effect of Dilute Alkaline Steeping on Mold Contamination, Toxicity, and Quality Parameters of Buckwheat Malt

Steeping in dilute sodium hydroxide (NaOH) was investigated with the primary aim of reducing molds and preventing toxicity of buckwheat malt. Samples of common buckwheat (Fagopyrum esculentum) obtained from Montenegrin farmers in the mountain area of northern Montenegro were steeped in 0.1, 0.2, and 0.3% NaOH. The effects of these solutions on mold contamination, ochratoxin A (OTA), out-of-steep moisture content (SMC), rootlet length, total nitrogen, total soluble nitrogen (TSN), free amino nitrogen (FAN), diastatic power (DP), and color of buckwheat malt were evaluated. Steeping in 0.1, 0.2, and 0.3% NaOH reduced the levels of molds from 105 to 103 CFU/g and steeping in 0.2% NaOH destroyed some of the mold genera. Steeping in 0.1, 0.2, and 0.3% NaOH reduced the level of OTA, especially in 0.2% NaOH, where the level of OTA after the malting process was below food safety regulations (5 μg/kg), and in 0.3% NaOH, where the level was below the limit of detection (0.1 μg/kg). Steeping in 0.1, 0.2, and 0.3% NaOH significantly (P < 0.05) increased levels of SMC, TSN, FAN, DP, wort color, and pH. However, it significantly reduced (P < 0.05) the level of extract and length of rootlets. The level of OTA contamination in stored buckwheat malt, which contained Penicillium genera, significantly increased (P < 0.05) over a period of 60 and 90 days. Steeping in 0.2% NaOH is proposed as a method for the reduction of mold and OTA contamination during buckwheat malting as well as prevention from further OTA production during storage

Extracts of fava bean (Vicia faba L.) seeds as natural coagulants

In this study, applicability of extracts from fava bean seeds (Viciafaba L.), as natural coagulants, was investigated. Coagulants were obtained by extraction, with distilled water or NaClsolutions, from grinded seeds and were applied as coagulants, in various doses, in synthetic water having different initial turbidities and pH values. Presence of NaC1 in water showed that increasing the ionic strength results in greater amount of extracted compounds, but it does not affect coagulation activity. Appling different doses of coagulant in water showed that the best coagulation activity is achieved by adding dose of 0.125 m1/1. The conducted experiments confirm positive coagulation properties of these extracts, therefore it can be concluded that they have great potential as natural coagulants. C) 2015 Elsevier B.V. All rights reserved