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Investigation of deep eutectic solvent-modified oat straw as an efficient adsorbent for Zn(II) ion removal: structural and kinetic study
No full textThis study investigated the potential of waste biomass, oat straw (SO), as an adsorbent for Zn(II)
removal from aqueous solutions. A selected deep eutectic solvent was used for OS modification
(DSO). Structural changes after modification were confirmed by Scanning Electron Microscopy
(SEM) analysis. To improve its adsorption
properties, the DSO was immobilized into alginate beads, IDSO. The adsorption study was done
in batch system. Adsorption capacities of Zn(II) ions removal from aqueous solutions were
evaluated for native, modified, and immobilized oat straw. The maximum adsorption capacities
for Zn(II) ions were 22.4, 51.4, and 104.78 mg/g for SO, DSO, and IDSO, respectively, indicating
a significant improvement of adsorption properties after modification and immobilization of native
material. A kinetic study revealed that the adsorption process follows a pseudo-second-order
model, suggesting that chemisorption is the rate-limiting step during Zn(II) ion adsorption on to
investigated materials. The SEM analysis provided visual evidence of the structural changes
induced by DES treatment, correlating with the observed increase in adsorption capacity. These
findings underscore the effectiveness of DES-modified biomass in metal ion removal, offering
promising insights for sustainable water purification strategies
Електрохемијска синтеза прахова и електрофоретско таложење превлака - од алуминијум оксида до биокерамичких материјала
No full textCharacterisation of strontium-substituted hydroxyapatite as potential biomedical material
No full textINTRODUCTION: Owing to its similarity to the inorganic part of the natural bone, excellent bioactivity, biocompatibility,
and ability to stimulate the osteoconductive process, synthetic hydroxyapatite (HAP) is very often the material of
choice for biomedical applications. Diverse ions can be found as substitutes within natural bone structures, each playing
a distinct and crucial role in the physiological processes governing the lifecycle of bones [1]. Among them, strontium ion
has a very important role for the acceleration of osteogenesis and the inhibition of osteoclasts activity [2]. Current
research aims to provide physico-chemical characterization of synthesized HAP and strontium substituted HAP (Sr-HAP)
powders obtained by varying strontium concentration (10, 20 and 40 mol.%) in the starting solutions.
EXPERIMENTAL: HAP powder was synthesized by wet chemical precipitation, using aqueous solutions of Ca(NO3)2
4H2O (Merck, p.a.) and (NH4)2HPO4 (Sigma-Aldrich, ≥99 %). By adding NH4OH (CENTROHEM, p.a.), pH value was adjusted
to 10. The obtained precipitate was heated up to 90 °C. The same procedure was followed for Sr-HAP powder syntheses,
by adding Sr(NO3)2 (Sigma-Aldrich ≥99.0 %) and maintaining the (Ca + Sr)/P ratio at 1.67 in the mixed Ca2+/Sr2+ solution.
Synthesized powders were characterised by FTIR spectroscopy (Nicolet IS-10, Thermo Fisher Scientific), XRD analysis
(Philips PW 1710, Philips, The Netherlands), TG analysis (Netzsch STA 449 F5 Jupiter instrument), and FE-SEM analysis
(JSM-7001F, JEOL Ltd, Japan).
RESULTS AND DISCUSSION: FTIR spectra revealed the presence of carbonate-substituted hydroxyapatite in both pure
and Sr-substituted HAP powders. The powders showed a granular, homogeneous morphology without the Sr separation.
XRD analysis revealed that the amount of incorporated Sr in the HAP structure increased with increased Sr concentration
in the starting solutions. Thermal stability of the Sr-HAP powders decreased with increased Sr concentration.
CONCLUSIONS: Physico-chemical characteristics of Sr-HAP powders are directly dependent on Sr ion concentration
in powders
Bioactivity of gentamicin-loaded hydroxyapatite/poly(vinyl alcohol)/chitosan composite coatings aimed for orthopedic application
No full textINTRODUCTION: Following orthopedic surgery, bacterial infection may lead to significant complications related to
inflammation in the peri-implant region, including the potential for implant loosening. To address this concern, the
surface of metallic implants was modified through the application of bioactive and antibacterial coatings, aiming to
mitigate these issues.
EXPERIMENTAL: HAP/PVA/CS/Gent coatings was single-step electrophoretically deposited from four-component
aqueous suspension containing 1 wt.% hydroxyapatite powder (HAP, particles < 200 nm particle size, Sigma-Aldrich),
0.1 wt.% poly(vinyl alcohol) (PVA, medium molecular weight 89 to 98 kDa, 99 % hydrolysed, Sigma-Aldrich), 0.05 wt%
chitosan powder (CS, medium molecular weight, 190 to 310kDa with 75 to 85 % deacetylation degree, Sigma-Aldrich), and
aqueous gentamicin sulfate solution (Gent, concentration 50 mg/ml, Sigma-Aldrich) on titanium plates (Sigma-Aldrich).
Antibacterial activity of HAP/PVA/CS/Gent coating was evaluated against Staphylococcus aureus TL (culture collection-
FTM, University of Belgrade, Serbia) and Escherichia coli ATCC 25922, while kinetics of antibacterial activity was monitored
according to our previously published data [1]. In vitro cytotoxicity assay was performed towards two fibroblast cell lines
of different origin-mouse origin cell line (L929 (ATCC CRL-6364)) and human lung origin cell line (MRC-5 (ATCC CCL-171)) [2].
To evaluate the statistical significance of the biological assay results (antibacterial activity, cytotoxicity and ALP activity),
one-way analysis of variance (ANOVA) followed by a multiple comparisons posthoc test was used.
RESULTS AND DISCUSSION: HAP/PVA/CS/Gent coating exhibited strong antibacterial effect against both S. aureus
and E. coli, especially pronounced against S. aureus, causing bactericidal effect. Cytotoxic effect of HAP/PVA/CS/Gent
coating was not pronounced in investigated MRC-5 and L929 cell lines. MRC-5 fibroblast cells in contact with
HAP/PVA/CS/Gent doubled alkaline phosphatase levels compared to their contact with the control samples
(HAP/PVA/CS), indicating good osteogenic properties.
CONCLUSIONS: Electrophoretically deposited HAP/PVA/CS/Gent bioceramic coatings on titanium, demonstrated
significant potential as implants in orthopedic practice, functioning as drug carriers. Not only do they possess
antibacterial properties, but they also exhibit no adverse effects on living tissue
Investigation of multi-cycle usage of nanophotocatalysts in degradation of thiophanate-methyl
No full textThe presence of different organic pollutants in water leads to the need to apply different technologies
and processes for their removal. Organic pollutants can cause several negative impacts on
surrounding environment, inducing detrimental effects on living beings. Fungicides represent one of
the biggest groups of crop protective agent with increased yearly consumption, frequently ending up
in non-target organisms. Therefore, aim of this study was to determine the possibility of using two
synthesized nanocatalysts Ag-P25 and Ce-P25 in several consecutive removal cycles of present
pollutant in water. Catalysts were applied in process of photocatalytic degradation of fungicide
thiophanate-methyl at atmospheric conditions. After each irradiation cycle, catalysts were collected,
rinsed, dried, and applied in upcoming operational run. Fabricated catalysts were also likened to
starter TiO2 material. After fifth cycle, FTIR and XRD characterization techniques were used for
proving stability of materials. Obtained results show that Ce-P25 possesses (98%) better stability than
Ag-P25 (96%), but base TiO2 (99%) has the best stability and efficiency after second cycle. Gathered
findings can open a new way of employing photocatalysis as a process for treatment of polluted waters
from various industries
Degradation of dye crystal violet released from the textile industry
No full textTextile industry wastewater is a significant source of pollution, often containing hazardous organic
dyes like Crystal Violet (CV). Photocatalytic degradation using semiconductor materials such as
titanium dioxide (TiO2) presents a promising solution for wastewater treatment due to its effectiveness
in breaking down organic pollutants under UV irradiation. This study investigates the efficiency of
TiO2 as a catalyst for the photodegradation of CV removed from textile wastewater. Experimental
trials were conducted in a batch reactor under UV irradiation, with CV (20 ppm) and varying
concentrations of TiO2 catalyst. Results revealed a significant reduction in CV concentration with
increasing catalyst dosage (to 0.1 g/L) and irradiation time. The optimal conditions for maximum
degradation efficiency were determined, highlighting the potential of TiO2 photocatalysis for textile
wastewater treatment. Furthermore, the kinetics of CV degradation were analyzed to understand the
reaction mechanism and rate. The degradation of the dye (20 ppm) was 98% for 95 min with 0.1 mg/L
TiO2. This research contributes to developing sustainable and efficient methods for treating textile
wastewater, addressing environmental concerns associated with dye pollution
Effect of phosphate glass and biochar on rose growth chemical durability evaluation of sintered fly ash based glass
No full textFertilizers with controlled release (CRF) are materials that have nutrients for the plant and can be dissolved after a certain time from the moment they are introduced into the soil. They are available to the plant much longer than conventional fertilizers. Phosphate glasses (PG) are quite interesting for controlled release systems due to their low chemical durability. Although pure PG have highly hygroscopic nature, their chemical durability can be compositionally controlled [1,2]. Biochar is the product of biomass pyrolysis, a process where organic substances are broken down at temperatures ranging from 350 °C to 900 °C in a reduced oxygen thermal process. Biochar applications have an effect on soil improvement, waste management, climate change mitigation and energy, and consequently might have social and economic benefits. Biochar improves soil physiology and increases productivity, assisting with crop residue management [3,4].
This paper presents the results of testing the effect of PG and biochar from plum stones (PSB) on rose plantings (sort Lavaglut). The control sample were rose plantings without fertilizer addition.
The phosphate glass (45.4P2O5•25.6K2O•14.5CaO•3.1SiO2•9.3MgO•1.2ZnO•0.9MnO2) was prepared from reagent grade raw materials. The glass mixture was melted at T = 1230 °C for t = 1h in an open porcelaine crucible in an electric furnace and the melt was quenched on a steel plate. Phosphate glass and biochar were added in a variety of dosages. The application of 1 g of phosphate glass and the application of 10 g of PSB had the greatest effect on increasing the average height of plants. The application of PG and biochar had no significant effect on the average number of formed branches in the crown, as well as on the average number of newly formed branches. Higher doses of PG (3 g) and PSB (10 g) have a favorable effect on increasing the average number of formed flowers. The chemical analysis of the plant material at the end of the vegetative cycle determined: increase in phosphorus and manganese content in all tested varieties; the highest content of zinc was determined in the variant where 2 g of PG was used; the calcium content was increased in all tested varieties. The data obtained within the scope of this study indicates that PG and PSB fertilizers have a positive effect on rose plant growth
Comparison between hydrochar and its alkali modified form in the removal of Cd(II) ions from aqueous solution
No full textThe alkaline activation could be useful to improve the adsorption abilities of hydrochars. In this
regard, the aim of this work was a comparison of the efficiency of non-modified (HPL) and modified
hydrochar (MHPL) forms during the adsorption of cadmium (Cd) ions from aqueous media. It was
found that MHPL had a higher capacity (qm=19.60 mg/g) and a different mechanism of bonding than
HPL (qm=11.76 mg/g). The Langmuir isotherms model best described Cd(II) adsorption by HPL, while
the Freundlich isotherm model better-described adsorption by alkali modified form. The SEM/EDS
and the FTIR analysis confirmed that there is a structural difference between these two new
adsorption materials, which might be attributed to the influence of the NaOH treatment. Also, the
FTIR analysis showed that MHPL adsorbent most binds Cd ions using oxygen functional groups. It
can be concluded that this paper also confirmed that alkaline modification improves the adsorption
capacity of hydrochar
Required quality parameters of clay for its further application
No full textClays are used in various industries such as: ceramic industry, porcelain (kaolinite clay),
refractory industry for making molds (montmorillonite clay), while clays with an increased
content of impurities are used in pottery. Each user has their own clearly defined quality
requirements that this raw material must meet. The quality of clay is determined by its chemical
and mineralogical composition, and the presence of impurities. They are made of finely dispersed
particles and their composition includes silicate type minerals. They consist of one or more main
minerals (kaolinite, hydroliskuni-illite, montmorionite and other aluminum silicates) and various
impurities that can limit its further application (quartz, zircon, apatite, garnets, iron carriers and
others). Silicates that are an integral part of clay can be crystalline (group of kaolin, pyrophyllite,
montmorionite, illite and halloysite) and amorphous (alophane). Phyllosilicates are
representatives of the crystalline group. They contain silicon, aluminum and significant amounts
of water. Differences in mineral composition are mainly due to different proportions of silicon and aluminum. The article shows the basic characterization of clay, on the basis of which the
quality of the trench raw material is determined. The obtained results are the basis for designing a
suitable preparation procedure in order to obtain a product of a more satisfactory quality for
further use (eg iron removal is done by magnetic separation)
Characterization of sphalerite concentrate from “Rudnik” deposit
No full textIn order to carry out comprehensive tests on the leaching performances of sphalerite concentrate
obtained by flotation of ore from the “Rudnik” Rudnik deposit, this paper presents its detailed
characterization. Structural characterization included detailed chemical, XRD, qualitative and
quantitative mineralogical and SEM/EDS analyses. The chemical and mineralogical composition
of the sphalerite concentrate, the grain size and intergrowths, together with structural and
paragenetic relationships were determined. Following mineralogical composition is found:
sphalerite, chalcopyrite, pyrite, galena, limonite, rutile, native silver/gold, silicates, and quartz.
Sphalerite is the most abundant mineral in observed structure. It mainly occurs as liberated,
while only a small part is in the form of simple to complex structural intergrowth, most often
with chalcopyrite, followed with pyrite, galena, tailings and inclusions with chalcopyrite. The
sphalerite grain size ranges from about 10 μm to over 350 μm. It contains visible native
silver/gold. Based on a detailed mineralogical analysis, it is possible to choose an adequate
composition of the leaching solution and predict the behavior of sphalerite in the selected
leaching solution