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Polyphosphate glass as fertilizer for plant seedlings
No full textPolifosfatno staklo, u kome je molski odnos (M2O + MO)/P2O5 >1, koje sadrži i mikroelemente Zn2+, Mn2+, Fe3+ i Cu2+, korišćeno je u supstratu za proizvodnju rasada cveća i povrća. Eksperimenti su izvedeni u stakleniku na Poljoprivrednom fakultetu u Beogradu i u laboratorijama ITNMS. Ispitivano je ponašanje polifosfatnog stakla prilikom rastvaranja u dejonizovanoj vodi i 2% rastvoru limunske kiseline na temperaturama od 20, 30, 37 i 50 °C. Ispitan je uticaj vremena rastvaranja na normalizovani gubitak mase (fm) i normalizovane koncentracije jona (fi). Određene su i konstante brzina rastvaranja(kw-dejonizovana voda, kc -2% rastvor limunske kiseline). Vrednosti kc su veće od vrednosti za kw, što potvrđuje uticaj rastvarača i temperature na proces rastvaranja. Rezultati su pokazali pozitivan efekat polifosfatnog stakla na rast i kvalitet ispitivanih biljaka. Primenjena doza polifosfatnog stakla od 1 gl-1 pokazala je najbolji efekat na rast ispitivanih biljaka-rasada.Due to the dissolution properties the phosphate glasses can be promising materials for the development of new ecologically safe fertilizers. The complex polyphosphate glass with a molar ratio (M2O + MO)/P2O5 >1 and addition of microelements Zn2+, Mn2+, Fe3+ and Cu2+ were used in substrate for production of flower and vegetables seedlings. Dissolution tests were conducted in deionized water and 2% citric acid. The effects of the reaction time on the normalized glass mass loss (fm) and the normalized concentrations of the ions (fi) at 20, 30, 37 and 50°C were determined. Dissolution rate constants (kw - deionized water, kc -2% citric acid) were also determined (kw-0.0028-0.0094 gm-2, kc-0.029-0.011 gm-2). Values of kc were higher than those of kw, which confirms a significant effect of solvent type and temperature on the dissolution kinetics of glass. The experiments with plants (one vegetable and one flower) showed that the addition of phosphate glass caused an increase in yield and quality of plants. The applied dose of polyphosphate glass of 1gl-1 showed the best effect on the growth of the examined plant seedlings
Electrophoretically deposited hydroxyapatite-based composite coatings loaded with silver and gentamicin as antibacterial agents
No full textIncreasing need for improved, compatible bone tissue implants led to the intensive research of novel biomaterials, especially hydroxyapatite (HAP)-based composite materials on titanium and titanium alloy surfaces. Owing to its excellent biocompatibility and osteoinductivity properties, hydroxyapatite is often used as part of composite biomaterials aimed for orthopedic implant applications. In order to overcome persistent problems of bacterial infection, various antimicrobial agents and materials and their incorporation in such medical devices were investigated. This paper represents a comprehensive review of single-step electrodeposition on titanium of hydroxyapatite/chitosan/graphene composite coatings loaded with silver and antibiotic gentamicin as antibacterial agents. The improvement of mechanical and adhesive properties of deposited composite coatings was achieved by graphene and chitosan addition, while desirable antibacterial properties were introduced by including antibiotic gentamicin and silver. The biocompatibility of electrodeposited HAP and HAP-based composite coatings was evaluated by MTT testing, indicating a non-cytotoxic effect and high potential for future medical use as orthopedic implant coating
Leaching in acidic solutions as a part of hydrometallurgical recycling of copper from printed circuit boards (PCBs)
No full textElektrični i elektronski otpad sve više ugrožava životnu sredinu ali i predstavlja značajan izvor korisnih metala. To se posebno odnosi na istrošene štampane ploče. One omogućavaju dobijanje osnovnih metala na ekonomski efikasan i ekološki prihvatljiv način. Ekstrakcija metala iz štampanih ploča iziskuje kombinaciju fizičkih, pirometalurških i hidrometalurških postupaka. Predmet ovog rada je hidrometalurški postupak dobijanja bakra iz otpadnih štampanih ploča zbog prednosti u odnosu na ostale postupke. Težište rada je, pri tome, na analizi različitih mogućnosti kiselinskog luženja bakra iz elektronskog otpada - prvom koraku hidrometalurškog tretmana.Electric and electronic equipment waste (WEEE) has become more an more dangerous to the environment, but it represents a significant source of valuable metals. It especially refers to the printed circuit boards (PCBs). They allow recovery of various metals by technologies that are economically effective and environmentally friendly. Extraction of base metals from PCBs requires a combination of physical, pyrometallurgical and hydrometallurgical processes. The subject of this paper deals with the hydrometallurgical recycling of copper form PCBs due its advantages compared to the other technologies. This review emphasizes the role of leaching process in the recycling of PCBs, which is the first step in the overall hydrometallurgical process. Various types of acidic leaching treatments of PCBs are discussed and compared
An investigation of ibuprofen release from a clinoptilolitic zeolitic tuff modified with cationic surfactant
No full textThe biopharmaceutical performance of ibuprofen – surfactant modified zeolitic tuff
composites prepared in a one-step preparation procedure was evaluated by in vitro drug
release experiments. Furthermore, to reveal stability upon desorption, the release of surfactant
was also investigated. Results showed that the prolonged ibuprofen release from the tested
composites was achieved over a period of 8 h. The analysis of the drug release profiles
indicated to a combination of drug diffusion and ion-exchange as predominant release
mechanisms. A negligible surfactant desorption demonstrated during release testing alongside
with non-toxic nature of these materials may encourages further researches of these
functionalized mineral materials as prospective excipients for pharmaceutical application
Characterization of lanthanum-doped phosphate glass
No full textBecause their potential biomedical application, different types of phosphate based glasses were studied and evaluated for drug delivery applications and bone tissue engineering. The addition of lanthanum to modified apatite was found to improve its biocompatibility and lower the cytotoxicity against osteoblast. In this paper, glass-ceramic with the composition 42P2O5·40CaO·5La2O3·10Na2O·3TiO2 (mol %) was obtained by standard melt-quenching method. The raw materials used for glass synthesis were reagent grade (NH4)2HPO4, Na2CO3, CaCO3, La2CO3 and TiO2. Powder X-ray diffraction analysis confirmed the quenched melt to be vitreous. To examine the glass crystallization non-isothermal crystallization was studied using DTA. Samples were crystalized at the appropriate temperature according to the DTA analysis. The XRD technique was used to identify the phase composition of the crystallized bulk glass samples. XRD analysis of the powdered sample showed that during sintering the glass particles crystallized and the crystalline phases determined were: α-Ca2P2O7, β-Ca2P2O7, Ca10Na(PO4)7, LaP5O14, β-NaTiOPO4, Ca2P2O7∙4H2O, Ca(PO3)2, β-Ca3(PO4)2, Ca3(PO4)2, γ-Ca(PO3)2, NaCa(PO3)3. For α-Ca2P2O7, 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. The obtained phase composition of the glass-ceramic indicated its possible application as a bioactive material for bone tissue engineering
Corrosion of coal fly ash glass
No full textThe increasing production of coal fly ash waste from thermal power plants has compounded environmental and economical problems worldwide. Considerable research has been undertaken because of the environmental problems presented by the fly ash. The goal is to produce usable material from waste. The aim of this papier is to produce glass from fly ash and limestone that will have high resistance to dissolution and leaching. Obtained glass could have wide application in industry. Coal fly ash was mixed with 37% limestone and melted in electric furnace at T=1500 °C during t=1 h. The obtained glass sample was black, without visible residual gas bubbles. X-ray powder diffraction (XRD)analysis confirmed the quenched melt to be amorphous. To determine the chemical durability, glass sample was crushed and then sieved to grain size 0.3-0.5 mm. The corrosion test was performed in a distilled water, HCl and NaOH solution (0.01 M9 at T=95 °C for t=2h using 2 g of samples and 70 ml of solution. The results of corrosion test revealed a high durability of the glass sample. Potential application of this material would include use as: building blocks, anticorrosive container lining, matrix material in which radioactive wastes and heavy metals could be successfully solidified into the glass structure
Paulownia leaves and their hydrochar for Pb2+ ions removal from aqueous solution
No full textAdsorbents prepared from agricultural and industrial biowaste are being investigated as efficient
material for removal of various pollutants from wastewater. In this study, Paulownia leaves powder
and its hydrochar prepared from hydrothermal carbonization at 200°C was investigated as potential
adsorbents for Pb2+ ions from aqueous solution. Paulownia leaves and hydrochar at 200°C were
characterized by FTIR spectroscopy before and after adsorption of Pb2+ ions. The experimental
results showed that Paulownia leaves had better adsorption capacity (q=34.53 mg/g) than hydrochar
produced at 200°C (q=11.26 mg/g) and could be considered as effective biosorbent for Pb2+ removal
from wastewaters
Hidročađ dobijena od supstrata za gajenje gljiva kao adsorbent bakra iz vodenih rastvora
No full textU ovom istraživanju, korišćena je hidročađ supstrata za gajenje gljiva radi ispitivanja mogućnosti njegove primene kao adsorbenta za uklanjanje Cu2+ iz vodenih rastvora. Hidročađ je pripremana procesom hidrotermalne karbonizacije na temperaturi od 180 °C pri reakcionom vremenu od 1h. Strukturna analiza hidročađi vršena je pomoću FTIR-a. Analizom je potvrđeno smanjenje intenziteta kiseoničnih funkcionalnih grupa (KFG) usled adsorpcije Cu2+ što ukazuje da su ove grupe odgovorne za uklanjanje ispitivanog metala iz vodenog rastvora. Vrednost adsorpcionog kapaciteta iznosila je 37.5 mg/g. Dobijeni rezultati pokazuju da se ovaj materijal može koristiti kao efikasan adsorbent bakra
Improper Deposition of the Mining Waste as a Source of the Environmental Pollution: Case Study of the Lake Robule (Bor, Eastern Serbia)
No full textLake Robule is an extremely acidic water body located in the proximity of the town of
Bor (eastern Serbia) polluted with high concentrations of dissolved metal cations.
Polluted water drains from the lake into the Bor river. Acid mine drainage originates on
the slopes of the mine overburden deposit named Visoki planir located on the banks of
the Lake. Long term exposure of the pyrite in the overburden to oxygen and water led to
generation of the acid mine drainage. These acidic streams leach and mobilize metal
cations, which end up in the lake Robule, making this water body extremely acidic and
contaminated with metal cations. This situation could be avoided by proper deposition
and reclamation of the mining waste. Inadequate deposition of the overburden of the
Copper mine Bor and its impact on environment were analyzed in this paper.
Reclamation of the mining waste usually consists of technical and biological phases,
where terracing, stabilization, melioration and binding of mine waste occur. The quality
of technical reclamation can often have a decisive impact on the quality of biological
reclamation, surrounding environment and acid mine drainage generation process. In
the copper mine basin in Bor, technical reclamation was carried out only partially and
by forming high waste piles with narrow slopes. That has significantly limited the
chances for successful biological reclamation of the terrain, and the consequences of
this procedure were strongly eroded waste pile slopes without drainage channels, with
almost complete absence of spontaneous vegetation, leaving sulfide minerals in the pile
permanently exposed to water and oxygen
Technetium-99m as a Tracer for the Liquid Residence Time Distribution Measurement: Optimization of Different Radiotracer Parameters for Flow Meter Calibration
No full textFlow meters are essential part of equipment in almost all chemical and process industries. Knowledge of
the flow dynamics and flow of material through the reactor system is required to evaluate the performance of the
reactors, processes, operation and design. Traditionally this evaluation can be performed using chemical tracers.
Chemical tracer results are not always precise and they could not allow an online diagnosis. The samples
containing chemical tracer have to go to a lab for analysis and chemical tracers are less sensitive than radioactive
ones. Radioactive tracers are the only tracers capable of measuring the active residence time distribution (RTD)
with high degree of precision and give information on-line without stopping the process. In this work the application
of radiotracer method for RTD measurement in flow meter calibration is described. The RTD measurements of the
system were performed in pilot-scale perfect mixer in series reactor for flow meter calibration with Technetium-
99 m (99mTc) as a radiotracer in the form of pertechnetate ion (99mTcO4
-). The optimization of the parameters
included input signal of radiotracer, concentration of radiotracer and position of detectors. The measured data
were analyzed, and standard and relative deviations were quantified under different operating conditions. A plug
flow model was used to simulate the measured RTD curves and investigate the flow dynamics of the flowing water.
The results of the study showed that the optimum concentration of 99mTc for flow meter calibration was 0.3 ml
having activity 0.68 mCi. The standard deviation was σ=0.10 l min-1 and the relative deviation was 0.94%. The
results of the study can help in the operation and design of the existing systems and design of new ones