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Photocatalytic decomposition of difenoconazole from wastewaters
No full textDue to the rapid development of industry and growth of population, water consumption is increased.
Beside this, releasing of xenobiotics, which represent significant pollutants into watercourse, like
heavy metal ions, pesticides, paints, and solvents, made this problem much bigger. Therefore, they
can enter into aquatic organisms directly from industrial plants or into human bodies indirectly
through agricultural products. New technologies, including photocatalytic decomposition, are
necessary for wastewater treatment as a highly efficient and low-cost process. Photocatalysis implies
the degradation of various types of harmful organic substances to simple molecules such as CO2, SO2,
ions, and water. The applied process has no detrimental effect on the environment and does not require
additional chemicals for precipitation of the products. In this work, photodegradation of the pesticide
difenoconazole (DFC) using a TiO2-based photocatalyst was examined using doubled wall
thermoregulated quartz reactor. As a replacement for UVC radiation, solar imitated Ultra Vitalux
(UV) lamp (300W) was used. Determination of DFC concentration was performed using a UV
method. Degradation kinetics follows pseudo-first order. After 120 minutes, the DFC was completely
degraded. Chemical oxygen demand (COD) also confirmed that successfully indicating that this
process can be used in treating of industrial wastewater
The efect of La2O3 addition on the crystallization characteristics of polyphosphate glasses
No full textThe purpose of this study is to investigate the influence of La2O3 addition on the crystallization characteristics of polyphosphate glasses. Differential scanning calorimetry (DSC), and X-ray diffraction (XRD) methods were used to investigate the crystallization behavior of glasses. The addition of La2O3 (1-5%), at the expense of phosphate mole fraction in polyphosphate glass, raises the characteristic temperature of glasses, and resistance to crystallization. The glasses show complex crystallization leading to the formation of several crystalline phase
Complex crystallization of the potassium-niobium-germanate system
No full textPotassium germanate glass with the molar ratio 30K2O·34Nb2O·36GeO2 have been synthesized by the standard melt-quenching method. The crystallization behavior under the non-isothermal crystallization conditions was investigated by the DTA and XRD methods. The results showed that this glass exposed a complex primary crystallization
Slow pyrolysis – tool for improvement of fuel Properties of lignocellulosic waste
No full textPeach stones, a valuable agro-industrial by-product available in many worldwide countries,
comprise a renewable resource, which can be widely applied for multifunctional purposes. Its
important advantages such as high-energy value, low ash content, low price and abundance, make
peach stones an ideal fuel for energy production, but also for new materials synthesis. Although
peach stones pose properties, which allow them to be used with minimal physical/chemical
treatment, they often need further modification in order to improve their thermal properties, where
slow pyrolysis is frequently used. This study aims to provide a practical and effective solution to the
revalorization of wasted biomass originating from the fruit processing industry, through slow
pyrolysis to convert this waste into carbonaceous material – biochar. The results presented show the
main properties of obtained biochar for its possible applications as a solid fuel, comparing them
with the properties of the raw biomass material
Circular economy implementation in the development of fire-retardant materials used in construction, industry, and general-purpose products
No full textDuring a fire, passive fire protection systems are designed to prevent the spread of flames, smoke, and toxic gases. The new fire-retardant (FR) material, used for passive fire protection, is created by combining copolymers (VC-co-VAc) (Slovinyl KV 173) and PVC K70 with expanded graphite and plasticizers/modifiers such as diisononyl phthalate - DINP, diisononyl terephthalate - DINTP, dioctyl adipate - DOA, as well as plasticizers that are synthesized based on tertiary recycling of waste poly(ethylene terephthalate) (PET), 1-hexadecene, azodicarbonamide (ADC), tri(p-cresyl phosphate), epoxidized soybean oil (ESO) and acrylate emulsion (DH50, Ecrylic, or Flexryl, etc.). The obtained material's morphology was examined using an emission scanning electron microscope (FESEM) field. Tensile testing was used to determine the mechanical properties of the obtained samples, as well as Shore A hardness and toughness using the Charpy impact test. All samples obtained were tested according to non-flammability standards. To conform to the new trend of "green economy," the development of novel eco-friendly FRs with improved thermal and mechanical properties will include careful consideration of environmental protection and sustainable development
Overview of technologies for Zn extraction from hyperaccumulating plants: Current state of research and future directions
No full textIako u ranoj fazi istraživanja fitorudarenje je podstaklo interesovanje u ispitivanju metala poput Ni, Au i retkih zemalja (REE). Međutim zagađenje cinkom iz rudničkog otpada, topionica, letećeg pepela i drugih antropogenih izvora postalo je ekološki problem. Fitoremedijacija hiperakumulirajućim biljkama pokazala se kao jedno od rešenja za smanjenje tog zagađenja. Stoga se pojavila i potreba za korišćenjem ili odlaganjem biljaka-hiperakumulatora cinka. Pošto su ranije sprovedena ispitivanja određenih hiperakumulatora za ekstrakciju metala, slični hidrometalurški i pirometalurški postupci ispitani su i za Zn. Hidrometalurški pravac ispitivanja fokusiran je na proizvodnju grubih eko katalizatora za potrebe organske hemije ili separaciju metalnih hidroksida cementacijom. Ovo je postignuto kiselim luženjem pepela dobijenog sagorevanjem nadzemne biomase. S druge strane, pirometalurški pravac više je fokusiran na bezbedno i ekološki prihvatljivo odlaganje proizvoda sagorevanja poput pepela i biočađi, uz postizanje nulte emisije toksičnih gasova pri pirolizi biomase. Bez obzira na pristup, potrebna su dalja istraživanja kako bi se ispitala stabilizacija metala koji zaostaju u čvrstoj frakciji tokom sagorevanja kao i smanjenje sadržaja metala u emitovanim gasovima. Do sada nijedna od ovih tehnologija nije dovedena do poluindustrijskih razmera u ispitivanjima, mada postoji potencijal u povezivanju ova dva pristupa.Phytomining, although predominantly in its early stages on the broader scientific scope of investigation, has garnered interest in metals such as Ni, Au, or rare earth elements (REE). However, Zn pollution from mine wastes, smelters, coal ash and other anthropogenic sources has become an environmental problem. Phytoremediation by hyperaccumulating plants is one of the proposed solutions to mitigate the pollution. Therefore, a need to utilize or dispose Zn hyperaccumulating plants occurred. Since studies of certain hyperaccumulating plant species have been previously conducted in order to extract metal products, similar hydrometallurgical and pyrometallurgical techniques were tried with Zn. The hydrometallurgical route was more focused on producing crude eco catalysts for organic chemistry or separating metal hydroxides by cementation. This was achieved with acid leaching of the ash which was obtained by calcinating the aboveground plant biomass. On the other hand, the pyrometallurgical route was more focused on safe and eco-friendly disposal of combustion products such as ash or biochar, while achieving zero toxic gaseous emissions from biomass pyrolysis. Regardless of the approach further research is needed to investigate the stabilization of metals that remain in the solid fraction during combustion and lowering the metal content in produced gases. So far, none of these technologies have been brought to a semi industrial scale and there is the potential of linking those two approaches together
Bioactive antibiotic-eluting hydroxyapatite-based coatings obtained by electrophoretic deposition on titanium
No full textTitanium surface was modified by applying new composite, biocompatible, and bioactive hydroxyapatite/chitosan coatings with and without gentamicin using the electrophoretic deposition technique (HAP/CS, HAP/CS/Gent, HAP/CS/Gr, and HAP/CS/Gr/Gent). HAP/CS/Gent and HAP/CS/Gr/Gent coatings presented strong activity against both bacterial strains tested and even noticeably more against S. aureus, while their counterparts without the antibiotic did not exhibit antibacterial properties. The rapid and strong antibacterial effect monitored during the first 24 h coincides well with the initial burst effect of gentamicin observed on the cumulative release profiles. Presented results are a solid confirmation that bioceramic HAP/CS/Gent and HAP/CS/Gr/Gent composite coatings electrodeposited on Ti are promising biomaterials for further investigation and potential biomedical application as orthopedic and dental implant
Modified food wastes as potential sorbents for phosphate removal
No full textAnnually, around 1.4 billion tonnes of food worldwide is classified as waste. This waste,
usually disposed at landfills, poses a serious threat to both the environment and human
health. With appropriate modifications, food waste can be converted into value-added
products for the removal of organic and inorganic contaminants from aqueous solutions. In
this study food waste (peach, cherry and plum stones) were modified with MgCl2 and
pyrolyzed to produce biochar, a multifunctional highly porous carbon rich material with
improved properties for phosphate (PO43-) removal. The samples were categorized using the
Fourier transform infra-red (FTIR-ATR) technique, point of zero charge (pHpzc) and pH
suspension (pHsus). The experimental sorption results revealed that the modified plum stone
biochar (PSB-M) has higher sorption capacities than other materials. Kinetic adsorption
experiments demonstrated that the pseudo-second-order model was the most suitable one for
PO43- adsorption on PSB-M. The production of such a sorbent can be affordable considering
that the raw material is regarded as waste. Therefore, the findings of this research can be a
foundation for the synthesis of an effective phosphate sorbent, whose properties and
maximum sorption capacity should be further researched
Zagađenje zemljišta mikroplastikom u području Zasavice
No full textУВОД и ЦИЉЕВИ: Услед високих нивоа производње и употребе пластике узрокованих
индустријским развојем, копнена околина садржи алармантне количине одбачених отпадних
пластичних материјала. Једном када доспеју у природу, они подлежу деградационим процесима,
разлажући се на микроскопске фрагменте, познатије као микропластике (МП). МП се дефинишу као
пластични остаци мале величине (< 5 mm) који потичу из различитих извора као што су производи
за личну негу, хабање гума, различите пољопривредне активности, таложење атмосферских
честица, клизишта итд. Земљишна станишта последично постају једно од доминантних басена за
депоновање МП. Токсични ефекти присуства МП у животној средини су бројни. Штавише,
захваљујући јаком капацитету адсорпције, МП би могле коегзистирати са другим загађивачима као
што су тешки метали и органске честице, што представља нови еколошки ризик. Присуство МП је
откривено у екосистемима у којима готово да нема људске активности - дивљим областима
Северне Америке, планинским шумама Пиринеја, па чак и на врху Монт Евереста. Овај рад је имао
за циљ да истражи садржај микропластике у земљишту које окружује Специјални резерват природе
Засавица, указујући на значај овог свеприсутног загађивача који негативно утиче на квалитет
земљишта, живи свет и ланац исхране.
МАТЕРИЈАЛ и МЕТОД: Узорци земљишта су прикупљани помоћу лопате од нерђајућег челика и
текстилних врећа, на травнатој површини у близини Специјалног резервата природе Засавица, на
дубини од 0-20 cm. Узорци су сушени на ваздуху две недеље и просејани кроз сито од 2 mm. Након
просејавања, узорци су сушени на 60˚C у пећи до константне тежине, а затим су мерена три
репликата од укупно 15 g узорка за анализу. На почетку је земљиште третирано са 60 ml 30% H2O2
како би се разорила органска материја земљишта. Како би се постигла боља екстракција МП,
суспензија је подвргнута ултразвучном третману у трајању од 10 минута, имајући у виду да МП
имају тенденцију да буду инкорпориране у агрегате земљишта. Након тога, дигестија је настављена
на 60˚C током 24h. Изолација МП извршена је методом раздвајања по густини. Суви остатак
земљишта који је остао након дигестије прекривен је засићеним раствором NaCl. Густина раствора
NaCl била је 1,2 g cm-1. Суспензија је стављена у ултразвучно купатило на 15 минута и остављена
преко ноћи како би се честице могле редистрибуирати по густини. Горњи слој супернатанта је
филтриран кроз Whatman стаклени филтер (величина пора 1,6 µм, пречник 25 mm). МП су
посматране и пребројане помоћу поларизационог микроскопа (Carl Zeiss Jena Pol-U).
РЕЗУЛТАТИ и ЗАКЉУЧЦИ: У складу с резултатима, узорци земљишта су садржали 800 честица по
kg земљишта, односно у измерених 5 g земљишта у просеку смо нашли 4 честице. Преовлађујући
облици МП били су фрагменти, док је величина била у распону од 50-500 µм. Боја честица је била
бела/провидна. Претпостављени доминантни извори остатака МП на овом подручју, које се сматра
незагађеним, могли би бити производи за свакодневну употребу, као што су амбалажа за храну и
пиће, козметички производи, текстил, гуме итд. Претпоставља се да индустрија и пољопривреда не
доприносе у значајној мери доказаном присуству МП. Метода која користи засићени раствор NaCl
даје информације само о честицама полимера са густином мањом од 1,2 g cm-1. Стога се очекује
да ће екстраховане честице бити остаци полимера као што су LDPE и HDPE (полиетилен ниске и
високе густине), PP (полипропилен), ABS (акрилонитрил бутадиен стирен), PC (поликарбонат),
HIPS (полистирен високог утицаја), или PA (полиамид). Јасан увид у утицај МП на екосистем тек
треба да се испита. Будућа истраживања биће усмерена на утицај МП на важна физичко-хемијска
својства земљишта и живи свет, одређивање типа и карактеризација МП и њеног главног извора
порекла на проучаваном подручју, како би се у будућности примениле одговарајуће мере за
смањење загађења пластиком
The effect ultrasound sonification on nitric acid leaching of pyrolyzed printed circuit board powder
No full textNumerous electronic devices are put out of use every day, and most of them have printed circuit boards (PCBs) that are lased and imbued with various precious and valuable metals in abundant amounts. This makes PCB an unexploited resource of the future from whom many metals such as Cu, Zn, Sn, Al, Li, Co, Nd, Pd, Pt, and Ba can be extracted. Since leaching plastic polymers can lead to the vaporization of toxic fumes, to avoid this the PCB are pyrolyzed. The PCB is crushed and the pyrolyzed product is a powder that can easily be separated into metallic and nonmetalic fractions. The aim of this work is to investigate the influence of ultrasound sonification on the nitric acid leaching of pyrolyzed printed circuit board (PPCB) powder. The impact of ultrasound sonification had a positive effect on the leaching degree for all investigated metals except for Cobalt. The biggest difference in leaching degree was for Lithium while the smallest was for platinum. Because of the complexity of the PPCB powder system overall, the measurement of oxidation-reduction potential (ORP) didn’t yield any insight into the leaching mechanism since the measured values mainly followed the expected trend due to nitric acid degradation