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Removal of diesel pollution by biochar - support in water remediation
No full textWater contaminated with diesel oil represents one of the greatest challenges in waste water management. Water soluble fraction (WSF) is of particular interest because of its toxicity to aquatic organisms and discharge regulations set by environmental authorities. Biochar sorbents have attracted great attention, due to their low cost origin and advantageous properties as well as high sorption capacities in sorption processes. In this study, we have reported the synthesis and characteristics of novel biochar sorbent made from waste lignocellulosic biomass (peach stones (PS)) and evaluated its possible application in removal of diesel WSF from synthetic water. Physiochemical characteristics of the biochar sample were analysed by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) method, and Fourier-transform infrared spectroscopy (FTIR), along with the elemental analysis. Characterisation of PS biochar (PS-B) indicated high multi porous surface area (159.1 m(2) g(-1)) with the average pore diameter 2.7 nm. FTIR results indicated higher presence of aromatic compounds in PS-B as compared to PS. The sorption experiments performed in a batch system using PS-B resulted in more than 95 % removal of diesel WSF, reaching equilibrium after 5 h. Equilibrium data were well fitted by Freundlich isotherm, while the pseudo-second order equation fitted well the kinetic data, indicating chemisorption involving valency forces through the sharing/exchange of electrons between the sorbent and PS-B. Applications of ecotoxicology tests based on a microbial biosensor (Aliivibrio fischeri) have shown a significant toxicity reduction of water sample after the treatment with biochar
Forensic science and fractal nature analysis
No full textForensic photography, also referred to as crime scene photography, is an activity that records the initial appearance of the crime scene and physical evidence in order to provide a permanent record for the court. Nowadays, we cannot imagine a crime scene investigation without photographic evidence. Crime or accident scene photographs can often be reanalyzed in cold cases or when the images need to be enlarged to show critical details. Fractals are rough or fragmented geometric shapes that can be subdivided into parts, each of which is a reduced copy of the whole. Fractal dimension (FD) is an important fractal geometry feature. There are many applications of fractals in various forensic fields, including image processing, image analysis, texture segmentation, shape classification, and identifying the image features such as roughness and smoothness of an image. Fractal analysis is applicable in forensic archeology and paleontology, as well. The damaged image can be reviewed, analyzed, and reconstructed by fractal nature analysis
Kinetics and column adsorption study of diclofenac and heavy-metal ions removal by amino-functionalized lignin microspheres
No full textIn-depth kinetic and column adsorption study for diclofenac, DCF, heavy-metal and oxyanions adsorption on highly effective amino-functionalized lignin-based microsphere adsorbent (A-LMS) is examined. The A-LMS was synthesized via inverse suspension copolymerization of industrial kraft lignin with the amino containing grafting-agent (polyethylene imine), and an epoxy chloropropane cross-linker. The batch adsorption results indicated process spontaneity and feasibility of a high removal capacity: DCF(151.13) >>Cd2+(74.84)>Cr(VI)(54.20)>As(V)(53.12)>Ni2+(49.42 mg g(-1)). The quantum chemical calculated interaction energies reveal stabilization of the A-LMS/DCF complex through the electrostatics and van der Waals interactions. The results from the pseudo-second order and Weber-Morris fitting indicate a fast removal rate; thus, column tests were undertaken. The single resistance mass transfer model, i.e. the mass transfer (kfa) and diffusion coefficient (Deff), shows pore diffusional transport as a rate limiting step. The fitting of the fixed bed column data with empirical models demonstrates the influences of flow rate and adsorbate inlet concentration on the breakthrough behavior. Pore surface diffusion modeling (PSDM) expresses mass transport under applied hydraulic loading rates, calculated breakthrough point adsorption capacities: Cd2+(58.1)>Cr(VI)(54.1)>As(V)(50.9)>>Ni2+(42.9 mg g(-1))), without performing the experimentation on a full pilot-scale level, further confirms the high applicability of the A-LMS biobased adsorbent
Technologically Sustainable Route for Metals Valorization from Jarosite-PbAg Sludge
No full textBy-products from zinc hydrometallurgy are classified as hazardous waste with strong leaching toxicities. Even though numerous research papers are dedicated to valorizing valuable metals in it, the primary management route is still disposal or partial reuse, such as the Waelz process. Presented experimental research investigates possibilities of sulfidization and further processing as a technologically sustainable route for valuable metals valorization from non-standard jarosite-PbAg sludge. The comprehensive thermodynamic analysis was done by HSC Chemistry(R), through optimizing process parameters, i.e., temperature, sulfur addition, and selection of possible additives. Technological possibility of magnetic separation, flotation, and smelting of sulfidized material was also investigated; the results were below the values that allow practical application, due to the obtained texture of sulfidized jarosite, which does not allow the liberation of minerals. Smelting tests were performed on sulfidized jarosite with sulfur and without and with carbon as additive. By smelting sulfidized jarosite-PbAg sludge with added carbon in sulfidization stage at 1375 degrees C, obtained products were matte, slag, raw lead, and dust in which base, critical, and slag forming components were valorized. Valuable metals were concentrated in smelting products so as to enable further processing, which also could be interesting in the case of treatment of complex, polymetallic, and refractory primary materials, which represent a significant contribution to the circular economy
Influence of selective acid-etching on functionality of halloysite-chitosan nanocontainers for sustained drug release
No full textThe functionality of halloysite (Hal) nanotubes as drug carriers can be improved by lumen enlargement and polymer modification. This study investigates the influence of selective acid etching on Hal functionalization with cationic biopolymer chitosan. Hal was subjected to lumen etching under mild conditions, loaded under vacuum with nonsteroidal antiinflammatory drug aceclofenac, and incubated in an acidic solution of chitosan. The functionality of pristine and etched Hal before and upon polymer functionalization was assessed by ?-potential measurements, structural characterization (FT-IR, DSC and XRPD analysis), cell viability assay, drug loading and drug release studies. Acid etching increased specific surface area, pore volume and pore size of Hal, decreased ?-potential and facilitated binding of the cationic polymer. XRPD and DSC analysis revealed crystalline structure of etched Hal. Successful chitosan binding and drug entrapment were further confirmed by FT-IR and DSC studies. XRPD showed surface polymer binding. DSC and FT-IR analyses confirmed the presence of the entrapped drug in its crystalline form. Drug loading was increased for ?81% by selective lumen etching. Slight decrease of drug content occurred during chitosan functionalization due to aceclofenac diffusion in the polymer solution. The drug release was more sustained from etched Hal nanocomposites (up to ?87% for 12 h) than from pristine Hal (up to ?97% for 12 h) due to more intensive chitosan binding. High human fibroblast survival rates upon exposure to pristine and etched Hal before and after chitosan functionalization (>90% in the concentration of 1000 ?g/mL) confirmed that both lumen etching under mild conditions and polymer functionalization had no significant effect on cytocompatibility. Based on these findings, selective lumen etching in combination with polycation modification appears to be a promising approach for improvement of Hal nanotubes functionality by increasing payload, polymer binding capacity, and sustained release properties with no significant effect on their cytocompatibility
Cavitation Properties of Rendering Mortars with Micro Silica Addition
No full textMicro-silica is a highly efficient mineral additive whose role is reflected in improvements of microstructure packing, strength and durability of non-shaped composite building materials such as concrete and mortar. A comparative study of performances of rendering mortars with different quantities of micro silica was conducted. The experimental program included production of reference mortar based on Portland cement and quartz sand (CM) and three mortars with 5, 10, and 15 % addition of micro silica (SCM-5, SCM-10, and SCM-15). The effect that micro silica addition has on the thermal behavior and mechanical properties of mortars was discussed. Hydration mechanisms and thermally induced reactions were studied at temperatures ranging from ambient to 1100 degrees C by differential thermal analysis. The results were supported by X-ray diffraction analysis. The cementing efficiency of micro silica was assessed by cavitation erosion test. The changes in the morphology of mortar samples prior and upon cavitation testing were monitored by means of the scanning electron microscope imagining. It was found that 5 % of superfine micro silica (SCM-5 mortar) has positive effects on mechanical strengths (15 % increase in compressive strength) due to microstructure densification arising from the successive filling of voids by the micro silica. Addition of micro silica also improved the cavitation erosion resistance in comparison with reference cement mortar (SCM-5 showed cavitation velocity as low as 0.09 mg/min). This qualifies mortars with micro silica addition as building materials which can be safely employed in potential hydro-demolition environment
Efficient removal of Cd2+ from aqueous solution using subgleba of mushroom Handkea utriformis
No full textMushrooms are widely investigated and recognized as perspective materials for the removal
of various pollutants from wastewater effluents. In this study, mosaic puffball Handkea
utriformis was tested as a new biodegradable, but relatively stable material for Cd2+
adsorption from aqueous mediums. The fruiting body of Handkea utriformis goes through the
process of autodigestion, during which their inside – gleba is turned into a powdery, sporebearing
mass, and the lower portion of the fruiting body – subgleba, into a dark, dry, spongy
mass. The impurities and spores present on the surface of the subgleba can be removed in a
simple process of purification with acidic and alkaline solutions. The purification decreases
the hydrophobicity of the surface of this material, and therefore increases the number of
surface functionalities, knowing that subgleba consists of sugars, proteins and polymeric
pigments (melanins). The subgleba purified with 0.1M HCl and 0.1M NaOH (Sp) was used
for the removal of Cd2+ from the aqueous solution. The efficiency of the material for
adsorption of Cd2+ was investigated in a batch system under the constant initial concentration
of adsorbate and pH and different concentrations of the adsorbent. Composition and surface
morphology were characterized by using FT-IR spectroscopy, SEM and EDX analysis.
Concentrations of Cd2+, before and after adsorption, were determined by using Atomic
Absorption Spectroscopy (AAS). The Langmuir and Freundlich isotherm models, as well as
kinetic models, were evaluated to correlate experimental data. The results showed that kinetic
data were well fitted by a pseudo-second-order model. Isotherms studies revealed that the
best fit was achieved with the Langmuir isotherm model with a maximum adsorption capacity
of 15.2, 19.1 and 25.0 mg g-1 at 25, 35 and 45ºC, respectively
Removal of arsenic(III) oxyanions from wastewater using aminosilane-modified natural and synthetic zeolite
No full textSilanization of the natural and synthetic zeolites as well as their use as adsorbents for removing arsenic(III) oxyanions from wastewater are the topic of this paper. Two types of zeolite were used: natural zeolite-clinoptilolite from Zlatokop deposit, Vranjska Banja, Serbia,
previously converted to H + -form and synthetic zeolite, mordenite. The modification was
performed with solution (3-aminopropyl) triethoxysilane (APTES). The presence of APTES
on the surface of zeolite was confirmed using TG/DSC and FTIR analysis. The results showed
that natural aminosilane-modified zeolite has a higher adsorption capacity for arsenic(III)
oxyanions compared to mordenite prepared in the same way. The kinetic data follow the
Lagergren pseudo-second-order model. This model implies a chemical interaction between
As 3+ - ions and functional groups on the silanized zeolite surface
Characteristics and physical-mechanical properties of kaoliniyed granite
No full textDuring the long geological past, the rocks of the Adriatic block were formed, which includes the rim of Cer and the Adriatic base. The rim of Cer is characterized by igneous rocks - granite, granodiorite and Paleozoic shale, while the Jadar basin is built of lake sediments that include mainly clay, sand, gravel, sandstone, sandy limestone. Some of these constituents are classified as kaolin raw materials. Kaolin raw materials can be formed during hydrothermal decomposition, kaolinization, which implies physical and chemical changes of various rocks of igneous origin, which contain feldspar and mica, such as granite. As the study of silicate raw materials used in the construction and ceramic industry is a very important and continuous problem, within this paper a more detailed chemical-mineralogical-physical characterization of four kaolinized granite composites (KI, KII, KIII and KIV) from the Beli Majdan deposit-Jadranska Lešnica. Kaolinized granites are formed by subvolcanic decay of granite. In technological terms, these are weakly bound rocks, which are comminuted into smaller aggregates by the grinding process. The techniques used in this study to examine kaolinized granite composite samples included chemical analysis, X-ray diffraction (X-ray), differential thermal analysis (DTA), and ignition tests at three selected temperatures (1000, 1100, and 1250°C). Based on X-ray analysis, it can be concluded that the mineral composition of the kaolinized granite composite "Beli Majdan"-Jadranska Lešnica includes quartz, feldspar, mica, calcite/dolomite and clay minerals. The most common minerals are quartz and feldspar (aluminosilicate containing cations of alkali and alkaline earth metals). Minerals from the mica group as well as carbonates (Ca and Mg) occur in smaller quantities. The results of chemical analysis showed that the Al2O3 content in the tested composites ranged from 19.02 to 21.04%, and the Fe2O3 content from 1.48 to 1.65%. Additionally, the K2O content in the tested composites ranges from 5.32 to 6.45%, which indicates the presence of k-feldspar and muscovite, and the Na2O content from 1.78 to 2.64%. The results of DTA analysis in all four composites indicated the presence of quartz and clay minerals. The ignition color is from brick red to dark brown red. Based on the obtained experimental results, it can be concluded that kaolinized granite "Beli Majdan"-Jadranska Lešnica is a quality raw material for composing ceramic masses in the production of ceramic tiles. It acts as a solvent and can partially or completely replace feldspar in ceramic masses
Peach stone biochar as efficient adsorbent for Cd(II) removal from aqueous phase
No full textLignocellulosic waste biomass (LCW) represents valuable resource whose implementation could help growing world demands in improving environmental problems. Fruit stones, as waste from food processing industry, are contributing toward negative stresses on our natural systems through impacts associated with both waste production and its disposal. Sustainable waste management practice necessitates that industries must shift from the current linear model to a circular based economy, utilizing wastes generated as initial materials for the production of new products, such as fuels, chemicals or materials which might help in solving environmental pollution topics. Waste biomass materials can be converted into value-added products using thermochemical methods, such as pyrolysis, whereby biomass is efficiently converted into biofuels, biochars and different value added products. This paper present current development work and evaluates potential opportunities for food processing waste pyrolysis focusing on the conversion of peach stones (PS) to biochar. The wasted PS were first crushed, milled to desired dimensions and then pyrolysed, heating from 25 to 500 оС at 10 оС/min heat flow, and kept at 500 °C for 2 h. The resulting biochar (PS-B) was characterized to determine the potential of this products for Cd(II) sorption as well as to distinguish sorption kinetics of Cd removal between raw and pyrolysed material. Kinetic experiments were performed in isothermal batch system with mixing (200 rpm), at 25 oC, adding 0.1g of sorbent in 50 ml of Cd(II) solution, with initial Cd concentration of 100 mg/L. Experimental results were modelled with three kinetics (pseudo-first, pseudo-second order and Elovich equation) and one diffusion model (Weber-Morris). Results of kinetic modelling indicated chemisorption mechanism with different diffusional behaviour of the samples. The contact pH (pHsus) of these materials were 4.10 (PS) and 5.76 (PS-B), indicating higher –OH content in biochars, which was also confirmed by FTIR analysis. The experimental results indicated that PS-B has almost five times higher sorption capacity than the native material (PS), under the same operational conditions, 24.50 mg/g compared to 5.25 mg/g, respectively. Conclusively, the PS derived biochar can be used as an alternative to conventional sorbents in contaminated water treatment. Moreover, more research work needs to be conducted on this waste type to biochar in order to investigate optimal operational parameters as well as flow system behaviour