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EN
To explore the influence of reagents addition sequence of the pH regulator and the starch depressant on the anionic reverse flotation of iron oxide, flotation conditional experiments were performed on mixed low-intensity and high-gradient magnetic concentrates which is the flotation feed acquired from the iron processing plant. Besides, quartz crystal micro-balance with dissipative (QCM-D) was conducted to detect the adsorption phenomena of the flotation reagent on iron oxide sensors at different addition orders. The outcomes showed that the flotation performance using the pH regulator prior to the depressant was the best. For example, at 1.6 kg/Mg starch dosage, the recovery and separation efficiencies were improved by 18.3% and 21.2%, respectively, with keeping the concentrate Fe grade as high as 69.5%. Also, QCM-D frequency shifted by -41 Hz from 17 Hz to -24 Hz with increased dissipation from -2.6 x 10-6 to 8.2 x 10-6, indicating an increase in the mass of slightly-rigid starch adsorption layer on the surface of iron oxide under a strong alkaline condition with adsorption density of about 0.46 mg/cm2. On the other hand, under weak alkaline conditions, starch was adsorbed, and then the starch was desorbed upon the addition of the strong alkaline solution. Whereas, adding the pH modifier to create a strong alkaline condition enhanced the starch adsorption significantly with coordination and hydrogen bonds, and prevented the following adsorption of the anionic collector for more efficient reverse flotation of iron oxide minerals.
EN
The hydration structure of water molecule adsorption at different coverages of a monolayer on a pyrite (100) surface were simulated using the density functional theory (DFT) method. The results demonstrate that the Fe-O interaction weakens and the adsorption energy per water molecule decreases with increasing water coverage, except at a monolayer coverage of 12/12 (i.e., full coverage). H-S and H-O hydrogen bonds were formed on the nearest surface layer. When large amounts of water molecules adsorb onto the surface, the adsorbed water molecules can be divided into three layers: the layer nearest to the surface, the second nearest to the surface, and the layer farthest from the surface. The thickness of the former two layers is approximately 5.5 Å. The three layers have water densities of 1.12 g/cm3, 1.08 g/cm3, and 0.95 g/cm3, respectively, suggesting that there is a strong interaction between the pyrite surface and water molecules and the influence of surface structure on water adsorption reaches a distance of more than 10 Å. Dynamics simulations suggest that the water molecules close to the mineral surfaces are in an orderly arrangement while those far from the surface are disordered.
EN
In this study, the effect of medium saline water on the synergistic interaction between diesel and Triton X-100 in the flotation of oxidized coal was investigated. The results showed that the flotation yield of oxidized coal in saline water was higher than that in de-ionized (DI) water due to the promotion of diesel adsorption, which was attributed to the screening of electrostatic repulsion between diesel droplets and coal particles in saline water. Meanwhile, the flotation of oxidized coal could be significantly improved when Triton X-100 was added with diesel as a composite collector, and less Triton X-100 was required in saline water than that in DI water to achieve the same true flotation yield, indicating that saline water could increase the effectiveness of Triton X-100 in improving oxidized coal flotation. A mechanism study revealed that Triton X-100 was able to promote diesel adsorption on oxidized coal through emulsification, thus increasing the surface hydrophobicity of oxidized coal through hydrogen bonding between the headgroups of Triton X-100 and the oxygenated groups on coal surfaces. The non-ionic characteristic of Triton X-100 ensured its capability of enhancing oxidized coal flotation in both DI water and saline water.
EN
The ratio of the hydrophobic to hydrophilic species and their distribution on mineral surfaces significantly influences the floatability of sulfide minerals. Through the flotation test, the influence of different reagents on pyrite flotation was examined. The interaction mechanisms between copper xanthate and pyrite were evaluated using advanced analysis technologies, including contact angle measurements, zeta potential analysis, scanning electron microscopy, energy dispersive spectroscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The results show that the butyl xanthate in solution reacts with copper sulfate to form cupric xanthate, increasing the consumption of the collector butyl xanthate and resulting in lower floatability of pyrite. Cupric xanthate can be adsorbed on the pyrite surface through bonding with the sulfur sites. The adsorbed cupric xanthate on the pyrite surface undergoes redox reaction. The cupric xanthate is reduced to cuprous xanthate, and the sulfur on the surface will be oxidized. The adsorption products on the pyrite surface contain both cuprous xanthate and cupric xanthate. As the pH of a solution increases, the absolute value of the zeta potential of pyrite surface increased and the surface contact angle increased. Iron xanthate is also formed on the pyrite surface through a chemical reaction between the xanthate ions and pyrite, oxidation of xanthate ions to dixanthogen also takes place. Cuprous xanthate is the main hydrophobic substance on the pyrite surface, which can change the surface electrical properties and wettability of pyrite, and improve hydrophobicity of pyrite.
EN
Agricultural residues rich in lignocellulosic biomass are low-cost and sustainable adsorbents widely used in water treatment. In the present research, thermodynamics, kinetics, and equilibrium of nickel(II) and lead(II) ion biosorption were studied using a corncob (Zea mays). The experiments were performed in a batch system evaluating the effect of temperature and dose of adsorbent. Langmuir and Freundlich isotherms were used to study the equilibrium. Thermodynamic and kinetic parameters were determined using kinetic models (pseudo-first order, pseudo-second order, Elovich). Biosorbent characteristics were studied by Fourier-transform infrared spectroscopy, Scanning Electron Microscopy and Energy-dispersive X-ray spectroscopy. It was found that the hydroxyl, carboxyl, and phenolic groups are the major contributors to the removal process. Besides, Pb(II) ions form micro-complexes on the surface of the biomaterial while Ni(II) ions form bonds with active centers. It was found that the highest Ni(II) removal yields were achieved at 0.02 g of adsorbent and 70°C, while the highest Pb(II) removal yields were achieved at 0.003 g and 55°C. A maximum Ni(II) adsorption capacity of 3.52 mg∙g–1 (86%) and 13.32 mg∙g–1 (94.3%) for Pb(II) was obtained in 250 and 330 min, respectively. Pseudo-first order and pseudo-second order models best fit experimental data, and Langmuir and Freundlich models well describe the isotherm of the process. Thermodynamic parameters (ΔH0, ΔG0, ΔS0) suggest that the adsorption process of both cations is exothermic, irreversible, and not spontaneous.
EN
The process of sorption of chromium(III) ions with a stationary sorbent layer of bentonite clays was investigated. The main advantages of using bentonites in water purification technologies are described: powerful geological reserves, cheap process of rock extraction, easy preparation for transportation and use, possibility of using waste sorbents in other technologies that is why there is no need in costly regeneration. The influence of various factors (process duration, an adsorbent layer) on the degree of wastewater purification from chromium ions, the effect of pumping speed on the dynamic capacity of the sorbent was studied and the effective volume was determined. The adsorption efficacy increases with the increase of the adsorbent layer, what can be explained by the development of the active sorption surface. As the initial concentration of chromium ions increases, the time of appearance of the first traces of the contaminant at the exit of the column increases, as well as the total time to channeling. The results of the studies indicate a higher adsorption capacity of modified bentonite with respect to Cr3+ ions compared to its natural formula. The cleaning efficacy of the solution with a concentration of chromium ions of 0.5 g∙dm–3 is increased by 5% when using 15 g of modified bentonite and 6,5% in the case one uses 20 g compared to the natural form.
EN
Municipal wastewater may contain residues of different drugs causing severe chemical contamination of water bodies. However, the microbial degradation of Wastewater Treatment Plants (WWTP) may not eliminate such drug residues completely. The current work was designed to remove the Ibuprofen drug residues by using the Moringa Oleifera seeds. Various testing methods such as Brunauer, Emmett and Teller (BET), Transmission Electron Microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) were applied to assess the efficiency of such plant seeds in bioremoval of ibuprofen residues from municipal wastewater The batch reactor was used to find the optimum operating conditions using various parameters with different pH values, duration time, Ibuprofen concentration and various quantities of plant seeds. In the batch reactor, the operation conditions were: pH 7, duration time 150 min, Ibuprofen dose of 1000 mg/l, activated adsorbents and Moringa Oleifera seeds in the amount of 1000 mg/l. Moreover, the packed bed reactor was used to examine different parameters such as initial Ibuprofen concentration, flow rate and bed depth for 6 hours. It was found that the best conditions were 2 cm depth, and 25 l/hr flow rate. Meanwhile, the kinetic constants were studied by adsorption equilibrium with the isothermal Langmuir and Freundlich models. The best results were shown with the Freundlich isotherm, and the first pseudo order was more suitable for the removal of Ibuprofen by adsorbed activation of Moringa Oleifera seeds.
EN
Bentonite clay was utilized in this research as adsorbent element to remove the lead and copper ions from wastewater. Series of tests were performed at multiple parameters, such as pH solution, initial concentration of lead and copper ions, adsorbent mass, and contact time. The greatest removal was attained at pH 5, adsorbent weight of 0.5 g, initial heavy metal concentration of 10 mg/l, and a contact time of 60 minutes. The results revealed that bentonite clay is suitable in the removal of metal ions from polluted water. The ion exchange rate of lead was faster than that of copper. The isotherm for the adsorption of the lead and copper ions on bentonite clay was confirmed by the Freundlich and Langmuir isotherms which offered good consequences. The results indicated that bentonite was utilized as an efficient ion exchange element for the removal of heavy metal ions from polluted water. Fourier Transformed Infrared Spectrophotometer (FTIR) images of bentonite clay before and after adsorption showed the imbibition of metal ions by bentonite clay.
EN
In this research, the ability of calcareous soil to absorb ammonium was investigated and the effect of compost amendment as a natural organic source on ammonium adsorption was also studied. The pH, dissolved ammonium concentrations, ammonium adsorption capacity, and cation exchangeable capacity for the soil samples were analyzed in relation to an untreated control and treatment with compost under ambient temperature and different initial ammonium concentrations (10, 20, 30, 40, 50, 70, and 100 mg/L). The amounts of ammonium adsorbed increased along with initial concentrations of dissolved ammonium for control and treatment with compost. The models evaluated in this study included the Langmuir and Freundlich isotherms. Ammonium adsorption was found to conform to the Freundlich equation isotherm more than that with Langmuir. The highest adsorption capacity was exhibited by 100 mg/L added initial ammonium concentration. Adding compost as a source of organic matter enhanced the adsorption capacity of calcareous soil with an increase in the adsorption of 36%, which indicated that the organic matter is a key limiting parameter in the mechanism of ammonium adsorption. Ammonium adsorption by calcareous soils is an important process in identifying the ammonium nitrogen route in soil-water systems.
EN
The use of heavy metals in the manufacturing industry over the past few decades has eventually contributed to a rise in the flow of metallic compounds into wastewater and has raised significant ecological and health threats to living things. Adsorption is an excellent way to treat solid waste effluent, offering significant benefits such as affordability, profitability, ease of operation and efficiency. However, the price of commercial adsorbent namely activated carbon has soared due to its high demand. There is also a green improvement in this method by turning the commercial adsorbent into agricultural waste. In Malaysia, the oil palm waste is such suitable material that can be utilized for making activated carbon, since they are ample and easy to find. Additionally, part of them is agricultural waste that cannot be consumed (i.e. leaves and fronds). Hence, this study aimed to analyse the potential of activated carbon from agricultural waste, namely oil palm waste, in reducing the levels of heavy metals in industrial wastewater.
EN
Laccase from Trametes Versicolor (E.C. 1.10.3.2) was immobilized on the Fe3O4–graphene hybrid nanocomposite through the covalent attachment method (Lac/Fe3O4/GO). The effect of immobilization conditions on the activity and recovered activities such as contact time, the concentration of glutaraldehyde and enzyme was evaluated. The recovered activity of the immobilized laccase on the Fe3O4–graphene oxide nanocomposite was ca. 86%. Immobilized laccase unlike free laccase retained the activity and exhibited higher resistance to temperature and pH changes and also improved storage and thermal stability. Approximately 70% of relative activity for immobilized laccase was remained after being incubated for 2 h at 55 °C, but free laccase only remained 48%. Immobilized laccase retained 88% of initial activity after storage for 20 days, however, the free laccase only 32%. Finally, Lac/Fe3O4/GO capability was evaluated by the oxidation of phenol, p-chlorophenol, and 2,4-dichlorophenol. Lac/Fe3O4/GO was characterized by SEM, EDX, FT-IR, and AGFM.
EN
Adsorption is considered the most efficient and simple method that requires low costs. In this study, firstly, yeast (Saccharomyces cerevisiae) was used to adsorption the Remazol Red RB dyes to analyze the efficiency of yeast as an adsorbent of textile dyes as well as determine the particle size, pH, and optimum contact time. Testing of the particle size parameters was done with variations of 100, 170, and 200 mesh size. The optimum conditio was obtained in the particle size variation amounting to 200 mesh size with efficiency %E of 56.49%. Subsequent testing was conducted with variations in pH (5.6, 7, 8, and 9). The optimum condition was obtained at pH 6 with efficiency %E of 60.35%. The dyestuffs were conquerable with variations in time of 1, 2, 3, 4, and 5 hours, the largest %E gained was 90.01% throughout 4 hours. Secondly, the research also aimed at identifying the isotherm adsorption pattern. Adsorption in Remazol Red RB dyes fulfilled the isotherm pattern of Langmuir with a correlation coefficient R2 of 0.9521 and the maximum capacity of the yeast adsorption of 0.07 mg/g. Further research is expected to expand the analysis variation and the type of textile dyes used which can be applied to the actual textile dyes waste.
EN
The article examines the ability of natural clays to extract heavy metal ions from aqueous solutions by ion exchange. The process of extracting metal ions was considered on the example of the absorption of manganese, nickel and cobalt from natural waters. In order to study the chemical and mineralogical composition of natural kaolin, the following were used in the work: X-ray diffraction and X-ray phase methods, as well as IR spectroscopy. The article presents a comparative analysis of the adsorption of manganese, cobalt and nickel ions on natural kaolin under different temperature conditions. The nature of the interaction of the studied metal ions with kaolin was established. The results obtained on the adsorption of the ions under study show the efficiency of using natural kaolin clay for water purification.
EN
Two raw biomass materials from different sources were investigated: aluminosilicate obtained from rice husk and agricultural lignocellulosic waste from kenaf fiber. The properties of the optimal mixing ratio of biochar were investigated by using proximate analysis, ultimate analysis, thermogravimetric analysis, surface area and pore volume determination, Fourier Transform Infrared Spectroscopy analysis, X-ray diffraction, and Scanning Electron Microscopy. According to the proximate analysis, the ash content is increasing while the moisture content fixed carbon and volatile matter decrease. On the basis of the BET characterization finding, the surface area is increased proportionally to the increasing mixing ratio RHB: KFB (0.8:0.2, 0.5:0.5, 0.2:0.8). The SEM images showed that both biochars are suitable sources of blending because of the differences and the availability of good adsorbents. This study indicated that RHB and KFB as pure biochar have a great potential to be applied as adsorbents. However, blending is not giving the desired result to be used as an adsorbent.
EN
This study investigated the Octyl Phenol Ethoxylate (OPE) removal potentials of raw and treated industrial treatment sludges (ITS) at different pH. Experiments were conducted in a set of 500 ml Erlenmeyer flasks, into which OPE solutions of 300 ml with different initial concentrations (50-300 μg/l) were added into. Adsorption of Octyl Phenol Ethoxylate from an aqueous solution into ITS105 (T=105°C), ITS300 (T=300°C), ITS600 (T=600°C) and ITS450 (pyrolyzed, T=450°C) was carried out at a room temperature. The OPE adsorption rate increase in the treatment sludge processed at 600°C. As opposed to the sludge treated at 105°C, the adsorption rate decreased as the concentration increased. The reason for this was that the porous structure was degraded at 600°C, and the surface charge balance was disrupted. ITS300 had a lower adsorption capacity for Octyl Phenol Ethoxylate removal than ITS105, ITS600 and ITS450 (pyrolyzed). The treatment sludge pyrolyzed at 450°C conformed with the Freundlich isotherm at pH 4 (R2=0.94) and pH 7 (R2=0.89). The treatment sludge heat-treated at 600°C conformed with the Freundlich isotherm at pH 4 (R2=0.97), pH 7 (R2=0.98) and pH 10 (R2=0.99). Additionally, for ITS600, the Brunauer, Emmett and Teller (BET) isotherm was valid at neutral pH. The OPE adsorption coefficient for ITS600 at pH 4 and pH 7 was calculated as 1.05 L/μg and 1.083 L/μg, respectively. According to the BET isotherm (for ITS600) the qm values at pH 4 and pH 7 were respectively 8.21 μg/g and 2.92 μg/g. The temperature of the adsorption value obtained with the Temkin isotherm showed that the interaction between the OPE and the adsorbent substances was not a chemical or ionic interaction but probably a physical interaction.
16
Content available remote Regularities of adsorption of α-oxypropionic acid by natural zeolite
EN
Wastewaters from dairy processing factories contaminated with α-oxypropionic acid were monitored. Theoretical analysis of industrial wastewater treatment methods on zeolites of Sokyrnytsia deposit was carried out. The process of sorption of α-oxypropionic (α-oxypropionic) acid by natural zeolite of Sokyrnytsia deposit was considered. It was established that the most economically advantageous and safe is the method of adsorption using a natural sorbent - zeolite, which provides the lowest concentration of contaminants in treated wastewaters from dairies. An assessment of their number, localization features and measures of toxicological impact on the environment was done. The existing theoretical apparatus of description of adsorption processes was analyzed. The sorption properties of natural zeolite (clinoptilolite of Sokyrnytsia deposit) and activated carbon to α-oxypropionic acid were tested. Equilibrium values of adsorption capacity were calculated and corresponding isotherms at a temperature of 20° С were constructed. The porosity of the sorbent and its influence on the sorption properties were studied by the methods of physicochemical analysis. Infrared spectroscopic and electron microscopic studies confirmed the presence of the process of sorption by the surface of the internal pores of the zeolite of α-oxypropionic acid molecules. Experimental studies have confirmed the possibility of using natural zeolite for wastewater treatment of dairy factories. It was experimentally confirmed by physicochemical methods of analysis (electron microscopy, IR spectroscopy, microprobe analysis, mercury porometry) and was established that the process takes place both by the mechanism of ion exchange and physical adsorption. The content of carbon radicals in the zeolite matrix after the sorption process was confirmed by X-ray spectral microanalysis. The ability of zeolite to adsorb organic carboxylic acid radicals was confirmed by the results of IR spectroscopic studies. On the IR spectra there are strips of deformation and valence oscillations of the groups of the crystal lattice of the zeolite Si-O, Si-O-SiOH: 452, 990–1210, 1638, 3368 cm-1. The oscillation spectra of free OH groups in the region of 2600 cm-1 were revealed.
EN
Most methods used for the synthesis of functional nanomaterials contribute to the increasing amount of waste solvents. An environmentally friendly solution of this issue is the utilization of “green” procedures for a large-scale production of materials such as mechanochemical synthesis. Although, the beginnings of mechanochemistry date back to ancient times, it nowadays experiences a renaissance and attracts a lot of attention. Recently, mechanochemistry has been successfully implemented for the synthesis of diverse carbonaceous materials, i.e., activated carbons, ordered mesoporous carbons, graphene-based materials and carbon nanotubes, the usage of which ranges from adsorption, catalysis to environmental and energy storage applications. Undoubtedly, it becomes quite universal and powerful synthesis method. Hence, a review summarizing the current accomplishments in this field is needed.
EN
The paper investigates whether time and doses of powder activated carbon (PAC) effect adsorption rates of organic contaminants from water and proposes a new model of volume adsorption. Depending on the nature of the organic compounds present in water, a general description of the adsorption process may require a linear combination of adsorption models running at different rates and at different parameters of adsorption isotherms. The model showed a good fit with the measured data and could be used in designing adsorption units at water or wastewater treatment plants. The proposed set of model equations enables to predict the effects of PAC adsorption in both plug flow reactors and homogeneous reactors.
PL
Artykuł bada, w jaki sposób czas i dawki proszku węgla aktywnego (PAC) wpływają na szybkość adsorpcji zanieczyszczeń organicznych z wody, i proponuje nowy model adsorpcji objętościowej. W zależności od charakteru związków organicznych obecnych w wodzie ogólny opis procesu adsorpcji może wymagać liniowej kombinacji modeli adsorpcji działających z różnymi prędkościami i przy różnych parametrach izoterm adsorpcji. Model, na którym przeprowadzono badania, wpasował się w przykładowe dane, więc można go wykorzystać do projektowania jednostek adsorpcyjnych w oczyszczalniach wody lub ścieków. Proponowany zestaw równań modelowych pozwala przewidzieć skutki adsorpcji PAC zarówno w reaktorach z przepływem tłokowym, jak i reaktorach homogenicznych.
PL
Przedstawiono wyniki badań nad możliwością wykorzystania aktywowanych pirolizatów ze zużytych opon do adsorpcji z wody modelowych herbicydów: kwasu 2,4-dichlorofenoksyoctowego (2,4-D), kwasu 2-metylo-4-chlorofenoksyoctowego (MCPA) oraz kwasu 2-metylo-4-chlorofenoksypropionowego (MCPP, Mecoprop). Adsorbenty otrzymano w wyniku aktywacji pirolizatów w atmosferze CO₂ w temp. 1100°C, stosując różne czasy procesu. Wielkość adsorpcji wszystkich badanych adsorbatów była skorelowana z czasem aktywacji i stopniem rozwinięcia struktury porowatej adsorbentu. Najlepszy z adsorbentów (135 min long aktywacji) miał powierzchnię BET równą 255 m²/g i całkowitą objętość porów równą 0,447 cm³/g. Dla wszystkich adsorbentów i adsorbatów adsorpcja najefektywniej przebiegała przy pH 2-3. Z testowanych trzech modeli izoterm adsorpcji: Freundlicha, Langmuira i Sipsa najlepszą zgodność danych doświadczalnych i modelowych uzyskano dla równania Sipsa. Aktywowane pirolizaty są skutecznymi i jednocześnie obiecującymi adsorbentami do usuwania herbicydów z wody. Zwiększenie ich pojemności adsorpcyjnej jest potencjalnie możliwe wraz z większym rozwinięciem powierzchni właściwej za pomocą aktywacji chemicznej.
EN
Three tire pyrolysis chars were activated in a CO₂ atm. at 1100oC and used as adsorbents for removal 2,4-dichlorophenoxyacetic acid, 2-methyl-4-chlorophenoxyacetic acid and 2-methyl-4-chlorophenoxypropionic acid from their aq. solns. The amt. of adsorbed acids was correlated with the activation time and the degree of adsorbent surface development. The best adsorbent had a sp. surface area of 255 m²/g and a total pore volume of 0.447 cm³/g after 135 min long activation. The best adsorption efficiency was achieved at pH 2-3. The best compatibility of exptl. and model data was obtained for the Sips model.
EN
In the process, inorganic complexes of amidoamines obtained from the interaction of natural petroleum acid and oleic acids with diethylenetriamine have been developed and their effectiveness as inhibitor-bactericides has been investigated. The effect of the synthesized reagents on the kinetics of the corrosion process of steel and the activity of sulphate-reducing bacteria in 3% NaCl solution saturated with CO2 and in the biphasic water–isopropyl alcohol medium with H2S dissolved has been analyzed. The thermodynamic and kinetic parameters of the corrosion process were calculated. The adsorption of the complexes was investigated using the Langmuir isotherm and the correlation constant was determined. State of the metal surface was investigated by SEM method in CO2 and H2S media, with and without inhibitors, and the metal surface contact of complexes was studied by computer molecular simulation.
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