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Sorption of Pb2+ ions from wastewater by Paulownia leaves and their hydrochar
No full textIt is of great importance to treat wastewaters, which contain heavy metals in concentrations harmful to the environment, before their discharge into watercourses. The biosorption is powerful tool for the removal of heavy metals from wastewaters. Paulownia leaves become biowaste during wood processing in industry and represent possible biosorbent or source for production of efficient adsorbents. In this study, Paulownia leaves and Paulownia leaves hydrochar produced at 180 °C were used as adsorbents of Pb2+ ions and their efficiency was determined. Paulownia leaves and hydrochar, before and after adsorption of Pb2+ ions, were characterized by FTIR spectroscopy. It was observed that oxygen functional groups might were crucial for adsorption of Pb2+ ions. The preliminary adsorption test showed that leaves without structural changes had better adsorption capacity which was q=34.53 mg/g than hydrochar produced at 180°C, q=10.57 mg/g. Therefore, Paulownia leaves could be considered as efficient adsorbent for Pb2+ removal
Efficiency zeolite and apatite in mobility harmful heavy metals in soil and plants.
No full textPoznavanja mobilnosti teških metala Pb, Cd, Zn i radionuklida U predstvalja jedan od ciljeva zaštite, uređenja i racionalnog korišćenja poljoprivrednog zemljišta sa aspekta proizvodnje zadravstveno bezbedne hrane. Cilj istraživanja disertacije je proučavanje efikasnosti prirodnih mineralnih sirovina na bazi zeolita i apatita sa domaćih nalazišta u mobilnosti teških metala i radionuklida u zemljištima različitih fizičko- hemijskih karakteristika (pseudoglej i černozem) koristeći test kulture slačicu (Sinapis Alba L.) i suncokret (Hellianthus annuus L.). Afinitet, efikasnost, mehanizmi adsorpcije zeolita i precipitacije apatita utvrđeni su u sistemu kolona sa konstantnim pritiskom, pri različitim pH vrednostima (5.00, 7.00) osnovnog kontaminiranog rastvora (Pb, Cd, Zn, U) 300 mg l -1 u vremenskim intervalima 30, 60, 90, 120, 180 minuta. U svim varijantama došlo je do značajnih promena pH vrednosti filtrata. Najviše promene pH vrednosti filtrata, minimalna kolebanja u vremenskom intervalu, pri pH=5.00, zabeležili su osnovni rastvori Pb (7.69-7.87) i U (7.77-7.93) kroz kolonu sa apatitom i nešto nižim promenama za Cd i Zn. Promene pH vrednosti osnovnih kontaminiranih rastvora, pH =5.00, zabeležene su i nakon propuštanja kroz kolone sa zeolitom ali znatno manjeg intenziteta sa trendom promena U>Pb>Cd>Zn. Trend promena između apatita i zeolita nastupile su i kod osnovnog kontaminiranog rastvora pH =7.00. Zeolit i apatit procesima adsorpcije/precipitacije uspešno su imobilisali Pb, pri pH vrednosti osnovnog rastvora 5.00 i 7.00. U kolonama apatit je bolje imobilisao U, zeolit je bolji za imobilizaciju Cd, dok su za Zn pokazali veoma sličan afinitet. Zeolit i apatit dodati u količini od 20 g kg-1 zemljišta smanjuju sadržaj vodnorastvorljivih i lakopristupačnih oblika Pb, Cd i Zn u nekontaminiranom i kontaminiranom zemljištu. Kontaminacija pseudogleja i černozema sa Pb i U je negativno uticala na morfofiziološke osobine suncokreta, dok je uticaj za Cd i Zn zavisio od tipa zemljišta. Povećano prisustvo Pb i U na černozemu negativno je uticalo na slačicu, Cd i U u pseudogleju su uticali stimulativno, dok je uticaj ostalih teških metala i radionuklida na masu korena i nadzemnu masu različit i zavisi od tipa zemljišta. Dostupnost Pb i Cd biljkama je veća u pseudoglejnom zemljištu, najvećim delom se akumulira u korenu, sa malom translokacijom u nadzemne delove za Pb i dobrom za Cd i većim afinitetom kod slačice. Cink je veoma mobilan u pseudoglejnom zemljištu, sadržaj Zn u korenu je niži od sadržaja u nadzemnim delovima i kod suncokreta i slačice. Mobilnost urana je veća u černozemu, pri čemu najveći deo ostaje u korenu biljke. Upotrebom zeolita, posebno apatita smanjen je sadržaj mobilnih formi toksičnih metala i radionuklida u zemljištu, dostupnost biljkama, kao i sadržaj u korenu i nadzemnoj masi suncokreta i slačice.Knowledge of the mobility of heavy metals Pb, Cd, Zn and radionuclides U represents one of the goals of protection, regulation and rational use of agricultural soils from the aspect of production of safe food. The aim of the research thesis is the study of the efficiency of natural mineral materials based on zeolite and apatite from domestic deposits in the mobility of heavy metals and radionuclides in the soils of the different physicochemical characteristics (pseudogley and chernozem) using a test culture mustard (Sinapis alba L.) and sunflower (Hellianthus annuus L.). Affinity, efficiency, zeolite adsorption mechanisms and apatite adsorption precipitation were determined in a constant-pressure column system at 300 mg l-1 for different pH values (5.00, 7.00) of the basic contaminated solution (Pb, Cd, Zn, U) at time intervals 30, 60, 90, 120, 180 minutes. In all variants, significant changes in the pH of the filtrate occurred. The most significant changes in the pH of the filtrate, minimal fluctuations in the time interval, at pH = 5.00, recorded the basic solutions of Pb (7.69-7.87) and U (7.77-7.93) through the column with apatite and somewhat lower changes for Cd and Zn. Changes in the pH of the basic contaminated solutions, pH=5.00, were also recorded after leaking through the zeolite columns but with significantly lower intensity with the trend of changes U> Pb> Cd> Zn. The trend of changes between apatite and zeolite also occurred in the basic contaminated solution pH=7.00. Zeolite and apatite adsorption/precipitation processes successfully immobilized Pb at pH of the basic solution 5.00 and 7.00. In colonies, apatite better immobilized U, zeolite is better for immobilisation of Cd, while for Zn, they showed a very similar affinity. Zeolite and apatite are added in an amount of 20 g kg-1 soil to reduce the content of watersoluble and easily accessible forms of Pb, Cd and Zn in uncontaminated and contaminated soil. Contamination of pseudogley and chernozems with Pb and U negatively influenced the morpho-physiological characteristics of sunflower, while the influence of Cd and Zn was dependent on the soil type. The increased presence of Pb and U in chernozems had a negative impact on the mustard, Cd and U in pseudogley were influenced by stimulus, while the influence of other heavy metals and radionuclides on the root mass and above ground mass varies and depends on the type of soil. The availability of Pb and Cd plants is higher in pseudogley soil, mostly accumulating at the root, with a small translocation into the above-ground parts for Pb and good for Cd and greater affinity in the mustard. Zinc is very mobile in pseudogley soil, the content of Zn at the root is lower than the content in the above-ground parts and sunflower and mushrooms. Uranium mobility is higher in chernozem, with most of it remaining at the root of the plant. The use of zeolite, especially apatite, reduced the content of mobile forms of toxic metals and radionuclides in soil, availability to plants, as well as the content at the root and above ground mass of sunflower and mustard
Zeolites as potential drug carriers
No full textIn the last two decades, natural zeolites have emerged in biomedical applications due to their favorable physicochemical characteristics such as high adsorption capacity and specific surface, the cation exchange ability, and good biocompatibility. Although very similar to clays that have been traditionally used in pharmaceutical preparations, these mineral materials also require a comprehensive characterization prior to their use as potential pharmaceutical excipients, that is, drug carriers. In this chapter a brief summary on definitions, properties, functionality-related characteristics, safety, and regulatory aspects of pharmaceutical excipients is given. Special attention is focused on natural and surfactant-modified zeolites; an overview of techniques used for characterization of a starting mineral material as well as drug-modified zeolite composites relevant for their application as pharmaceutical excipients and potential drug carriers is presented
Graphene reinforced hydroxyapatite biocomposite coatings obtained by electrophoretic deposition on titanium
No full textBrzi razvoj istraživanja nanomaterijala koji sadrže grafen otkrio je da se njihova izuzetna svojstva mogu koristiti za biomedicinske primene, posebno u inženjerstvu tkiva i kao nosači lekova. U ovom radu su prikazani rezultati istraživanja biokompozitnih prevlaka na bazi hidroksiapatita koje su dobijene elektroforetskim taloženjem na titanskom supstratu i ojačane nanočestičnim grafenom, kao potencijalnih kandidata za implante koštanog tkiva.Fast ongoing research of graphene-based nanomaterials reveals that their exceptional properties could be utized for biomedical applications, especially in tissue engineering and drug delivery. Here, we summarized the results obtained on hydroxyapatite based biocomposite coatings produced by electrophoretic deposition on titanium substrate and reinforced by nanosized graphene, as potential candidates for hard tissue implants
Ispitivanje kinetike i termodinamike adsorpcije jona Zn2+ na granulisanom aktivnom uglju
No full textGranulisani aktivni ugalj (eng. granulated activated carbon, GAC),
komercijalni naziv Karbozjak, proizveden u preduzeću „Miloje Zakić” u
Kruševcu, ispitan je kao adsorbent za uklanjanje jona Zn2+.
Fizičkohemijskim analizama utvrđeno je da je ugljenik osnovna komponenta
− 63,3 %, BET specifična površina 1436 m2 g−1 i raspodela veličine čestica u
opsegu od 0,355−1,60 mm. Uzorak je homogenizovan pomoću avana i
tučka, ispran dejonizovanom vodom, sušen 2 h na 105 ºC, a zatim
kondicioniran u eksikatoru. Ispitan je uticaj mase adsorbenta, temperature i
kontaktnog vremena na sorpcioni kapacitet, kinetiku i termodinamiku
procesa. Sorpcioni kapacitet GAC/Zn2+ od 47,3 mg g−1 na 45 ºC, izračunat
preko Lengmirovog (Langmuir) modela, ukazao je da je ovaj ugljenični
materijal visoko efikasan adsorbent. Najbolje slaganje kinetičkih parametara
sa Veber- Morisovim (Weber-Morris) modelom ukazalo je da je
unutarčestična difuzija određujući stepen adsorpcije jona Zn2+. Adsorpciona
svojstva materijala potvrđena su strukturnom i površinskom karakterizacijom
primenom skenirajuće elektronske mikroskopije (SEM) i rendgenske
difrakcione analize (XRD). U skladu sa konceptom ponovne upotrebe
materijala i bioodrživosti, iskorišćeni GAC/Zn2+ adsorbent mogao bi se dalje
primeniti kao antimikrobni nosač (višenamenski materijal)
Separation of the Ps/Abs plastics using the Froth flotation
No full textFlotation is the process of separation based on the different physical-chemical characteristics of surfaces and their ability to wet with water. The process can be used for separation the primary and secondary materials. This paper presents the results of a laboratory study separation of plastic waste. The aim is to extract the PS plastics from the PS/ABS mixture. Experiments were carried out in a Denver cell at the pH 7 in presence of the Tannic acid as a depressant, and MIBC as a frother. The results showed that the PS plastics has a higher flotation rate constant value and high quality value fover 90%). The results indicate that the ABS and PS could be successfully separated by the froth flotation under the certain conditions. The obtained results were represented by the classical model of the first-order trying to describe the kinetics of plastics flotation with a good correlation coefficient
Prediction of indicators for solid waste management on national level using artificial neural networks.
No full textProblem upravljanja otpadom postoji od nastanka najranijih ljudskih naseobina, ali je posebno izražen u današnjim urbanim sredinama. Sa povećanjem gustine naseljenosti do koje dolazi usled porasta broja stanovnika i njihovog gravitiranja ka velikim gradovima, kao i sa ubrzanim napredovanjem industrije, savremeni čovek stvara daleko više otpada nego ikada u istoriji ljudskog društva. Napredak nauke i tehnologije dovodi do stvaranja novih, najraznovrsnijih proizvoda, koji, usled porasta životnog standarda i izmenjenih potrošačkih navika, imaju znatno kraći životni vek nego raniji proizvodi, samim tim i mnogo ranije postaju otpad. Sve ovo značajno usložnjava sakupljanje i tretman otpada. Sa druge strane, kao nikad do sada, otpad predstavlja značajan resurs koji može da se iskoristi za dobijanje energije ili novih proizvoda raznovrsne namene...Dealing with waste is a problem since the emergence of the earliest human settlements, but it is particularly pronounced in contemporary urban areas. With the increase in population density due to population growth and their gravitation towards big cities, as well as with the rapid advancement of industry, modern man creates far more waste than ever in the history of human society. Big progress of science and technology leads to the creation of new, more diversified products, which, due to the rise in living standards and altered consumer habits, have a much shorter life expectancy than earlier products, thus becoming much earlier a waste. All mentioned significantly complicates the collection and treatment of waste. On the other hand, as never before, waste represents a significant resource that can be used to generate energy or new products..
Application of raw volcanic rock found in etna valley as an adsorbent of chromates, arsenates and selenates
No full textThis paper aims to determine the potential of volcanic rock found in Etna valley as an adsorbent of heavy metals in anionic form (chromates, arsenates, and selenates). Characterization of the volcanic rock was done with chemical methods (AAS, AES, gravimetric analysis, XRF), physicochemical methods (XRD, FTIR, SEM, DTA, DTG) and physical methods (porosity measurement, Microscopy in transmitted light). Also, equilibrium adsorption capacity was determined. All the results of adsorption capacity were satisfying considering the mineral composition, granulation, and porosity. The removal efficiency of chromates was the biggest (above 30 %) with adsorption capacity of 15.6 mg Cr g(-1). The lowest adsorption efficiency was with the selenates, approximately 18 %
Adsorption of mycotoxins by unmodified and modified phillipsite
No full textIntroduction
Mycotoxins are secondary metabolites produced by various fungi, primarily belonging to Aspergillus, Fusarium, or Penicillium genera. The most common mycotoxins found in animal feed are the aflatoxins, ochratoxins, trichothecenes, fumonisins, zearalenone and ergot alkaloids. Consumption of mycotoxin-contaminated diet may induce acute and long-term chronic effects in animals and humans, resulting in teratogenic, carcinogenic and oestrogenic or immune-suppressive effects (Zhu et al., 2016).
One approach to reduce deleterious effects of mycotoxins is to use adsorbents in animal feed to bind mycotoxins efficiently in the gastrointestinal tract and prevent their adsorption in the digestive tract. The preferred adsorbents are aluminosilicates (natural zeolites and clay minerals). These adsorbents in their natural form are effective in binding aflatoxins but less effective in binding other mycotoxins. Chemical modification of these minerals with cationic surfactants results in an increased hydrophobicity of the surface and improved adsorption for the majority of the mycotoxins. Clinoptilolite, in its natural form, was effective in adsorbing aflatoxin B1 (AFB1), while clinoptilolite modified with cationic surfactants such as octadecyldimethylbenzyl ammonium chloride and benzalkonium chloride was effective in binding ochratoxin A (OCHRA) and zearalenone (ZEN) (Daković et al., 2005; Marković et al., 2017). Besides clinoptilolite, phillipsite modified with different levels of cetylpyridinium chloride was also shown to be an effective adsorbent for ZEN (Marković et al, 2017). Since adsorption of mycotoxins may be dependent on the type of surfactant, the aim of this research was to investigate how the modification of phillipsite with surfactant hexadecyltrimethyl ammonium bromide (HDTMA) would influence the adsorption of AFB1, OCHRA and ZEN.
Experimental Methods
A sample of Neapolitan Yellow Tuff (Campania, Italy) composed primarily of phillipsite (PHI), was used as starting material. The modified sample was prepared by treatment of a 10% aqueous suspension of starting material with the surfactant hexadecyltrimethyl ammonium bromide (HDTMA) in an amount equivalent to 100% of its external cation exchange capacity (ECEC) and denoted as PHB-100.
Mycotoxins, AFB1, OCHRA and ZEN were obtained from Sigma-Aldrich Co. Adsorption experiments were performed using the following procedure: duplicate aliquots of 0.1M phosphate buffer (pH 3 and 7) containing 2 ppm AFB1, 2 ppm OCHRA and 2 ppm ZEN in solution (10 mL) were added to 15 mL screw cap Falcon polypropylene tubes to which had been added 20, 10, 5 or 2 mg of PHI and PHB-100. In order to eliminate exogenous peaks, controls were prepared by adding 10 mL of 0.1 M phosphate buffer (pH 3 and 7) to Falcon tubes containing 10 mg of each adsorbent. All samples were placed on a rotating shaker for 30 min at room temperature, centrifuged for 5 min at 13000 rpm and 2 mL of the aqueous supernatant was removed for HPLC analysis.
Results and Discussion
Adsorption of AFB1, OCHRA and ZEN by PHI and PHB-100 at different pH values is presented in Figures 1 and 2. Adsorption of each mycotoxin increased with increasing amounts of PHI and PHB-100 in suspension. PHI showed a high adsorption for AFB1 at pH 3 and moderate adsorption at pH 7, while
adsorption of OCHRA and ZEN by PHI was low at both pH values (less than 10% for OCHRA and less than
20% for ZEN). Modified phillipsite showed increased adsorption for each mycotoxin at all investigated
amounts of adsorbents. Compared to the PHI, adsorption of AFB1 by PHB-100 was slightly increased at
pH 3 (from 80.0% for PHI to 85.2% for PHB-100), while a higher increase was observed at pH 7 (from
51.9% for PHI to 81.5% for PHB-100). A much higher increase in adsorption by PHB-100 was observed for
OCHRA and ZEN at both pH values. In conclusion both PHI and PHB-100 were efficient in the adsorption of AFB1 at pH 3, while the
presence of HDTMA at the zeolitic surface increased adsorption of AFB1 at pH 7. Unmodified PHI showed
low adsorption of OCHRA and ZEN at both pH values, while modification of phillipsite with HDTMA ions
significantly increased adsorption of both these mycotoxins
Synthesis of Phosphate Based Bioactive Glass-ceramics Scaffolds
No full textIn recent years, because of dissolution behavior, bioactivity and biocompatibility, there is an expanding interest in the development and application of phosphate-based glasses as biomaterials in medicine [1, 2]. These glasses are preferable to silica-based glasses because of their more controllable dissolution rate [3, 4]. Several techniques have been developed to fabricate bioactive porous glass-ceramic scaffolds for application in bone tissue engineering [5-7]. In this paper, the 3D macroporous bioactive glass-ceramic scaffolds based on 42P2O5•40CaO•5SrO•10Na2O•3TiO2 (mol %) glass were prepared by polyurethane (PU) foam replication technique and analyzed. The appropriate batch composition of raw materials was melted at 1250 °C for 0.5 h in a Pt crucible. Obtained glass samples were transparent, without visible residual gas bubbles. To obtain desired particle size (< 5μm), the glass sample was ground at 400 rpm for 1h in an SFM-1 Desk-Top Planetary Ball Miller, MTI Corporation. The polymeric template used for scaffold preparation was a commercial PU sponge. The sponge cubes were soaked into the glass slurry, compressed, dried, and thermally treated (650 °C, 1h) to remove the organic phase and to obtain macroporous glass-ceramic scaffolds. The sintering temperature for glass was chosen according to DTA and HSM experiment performed previously [8]. Scaffolds structure and morphology were analyzed by stereo microscope (EU Instruments) and a scanning electron microscope (MIRA X 3 TESCAN). The phase composition of the sintered scaffold was determined by XRD analysis using a Philips PW-1710 automated diffractometer. Figure 1, shows the structure of the PU sponge, used as a scaffold template that exhibits a 3D network of pores, which vary in size from 100 to 600 µm. In Figure 2, the SEM micrograph of the PU skeleton coated with glass particles is shown. As may be seen in Figure 3, the morphology of the scaffold sintered at T = 650 °C for 1h remains highly porous without a significant decrease in the pore size. The images revealed that the pore struts are well sintered. XRD analysis of the powdered scaffold showed that during sintering the glass particles crystallized and the crystalline phases determined are: Ca(PO3)2, β-Ca3(PO4)2, α-Ca2P2O7 and β-Ca2P2O7 (Figure 4). For β-Ca3(PO4)2 and β-Ca2P2O7 the bioactivity, i.e. the ability to promote the formation of apatite (HAP) layer after reaction with the surrounding body fluid has been reported [9]. The obtained phase composition and the microstructure of the as-prepared scaffold indicated its possible application as a bioactive material for bone tissue engineering [10]