Adsorption Values Research Articles

Synthesis of an Activated Carbon Based on Cardoon Waste and its Comparison to a Commercial Carbon in Terms of Physicochemical Characterization and Organic Dye Adsorption Performance

The present study aims to evaluate the possibility of using low-cost adsorbents based on Cardoon waste for the depollution of industrial effluents. After characterization of the raw cardoon waste [1], the carbonization was carried out at 350 °C in a muffle furnace. In order to show the performance of the method used to prepare this activated carbon (PC), a comparative study with a commercial carbon (CC) is performed. The obtained activated carbon and the commercial carbon were characterized by thermogravimetric analysis, scanning electron microscopy coupled with EDX, X-ray diffraction, Fourier transform infrared absorption spectroscopy and inductively coupled plasma atomic emission spectroscopy. Approximate analyses of moisture content, volatile matter content, ash content and fixed carbon content, acid-base surface functions, pH at zero charge and iodine value were performed. The obtained results indicate that the main characteristics of the activated carbon prepared at 350 °C are practically similar to those of the commercial carbon; a homogeneous porous surface, an interesting percentage of carbon, a high thermal stability and a disorganized graphitic crystalline structure, the iodine adsorption values on the two carbons are 409.887 mg/g for PC and 430.191 mg/g for CC. The adsorption of methylene blue (MB) on both carbons was performed. The kinetics and isotherms of MB adsorption on the two carbons were evaluated. According to the obtained results, the use of the prepared carbon in effluent treatment can be put into perspective.

Composite hydrogel based on chemically modified gelatin and PVA containing graphene oxide nanoparticles (CHGP-GOn)

The increased consumption of medications such as Chloroquine (CQN) during the Covid-19 pandemic, the excretion of this drug leading to an overload of CQN and its metabolites in sewage treatment plants, increased the necessity to adequate treatment for their removal. Water treatment using advanced processes can be enhanced through the utilization of adsorbent and absorbent materials, facilitating the removal of hard-to-treat compounds and enabling material reusability. The use of nanoparticles offers desirable attributes responsible for the adsorption process, maximising the feature of water treatment materials. In this context, graphene oxide exhibits high surface area and significant adsorption capacity due to its abundance of desirable functional groups for adsorbing contaminant molecules. However, the lixiviation from these materials represents an environmental problem. The functionalization of adsorbent materials with nanoparticles has been used to minimise the loss of nano-compounds. In this way, composite hydrogels synthesized with graphene oxide have demonstrated adsorption and absorption properties for emerging contaminants, including pharmaceuticals. Therefore, a composite hydrogel based on chemically modified gelatin and PVA containing graphene nanoparticles, with resistant reticulation and non-toxic compounds, synthesized for the first time, was employed for the removal of CQN from aqueous media. This hydrogel superabsorbent with morphological rough shows 175% capacity of swelling, positive tendency of charge on natural pH due to diverse functional groups, as well as point of zero charges at pH 9.1, amorphous features. The batch removal tests demonstrated a superabsorbent material (175% swelling), showing the best removal in Qe of 13.20 mg g −1 of Chloroquine, as well as a superior performance at natural pH. The adsorption kinetics were best described by the Elovich model, indicating multi-step resistance with intraparticle diffusion as the rate-limiting step, equilibrium in 240 min and a maximum adsorption capacity of 13.31 mg g−1. Furthermore, the isotherm exhibited spontaneous and exothermic adsorption, with low reversibility and randomness in the adsorption system. Besides, the maximum experimental adsorption capacity was 52.98 mg L-1 in 288 K. The material demonstrated promising reusability, retaining its adsorption capacity over three adsorption cycles and values of 14.26 followed by 4.830 and 2.280 mg g- 1, respectively. In conclusion, the composite hydrogel based on graphene oxide shows great potential as an efficient and eco-friendly approach for removing emerging contaminants, particularly pharmaceuticals like CQN, from aqueous environments.

Identification of Proteins Adsorbed on Hydroxyapatite Ceramics with a Preferred Orientation to a-Plane

Protein adsorption is essential for determining material biocompatibility and promoting adherent cell growth. In this study, we focused on the a-plane structure of hydroxyapatite (HAp). This a-plane structure closely resembles the crystal plane where apatite is exposed in long bones. We conducted protein adsorption experiments using HAp ceramics with a preferred orientation to a-planes (aHAp), employing bovine serum albumin (BSA), lysozyme, and fetal bovine serum (FBS) as protein models to mimic the in vivo environment. Higher zeta potential and contact angle values were found in aHAp than in HAp ceramics fabricated from commercial HAp powder (iHAp). Bradford-quantified protein adsorption revealed BSA adsorption of 212 ng·mm−2 in aHAp and 28.4 ng mm−2 in iHAp. Furthermore, the Bradford-quantified protein adsorption values for FBS were 2.07 μg mm−2 in aHAp and 1.28 µg mm−2 in iHAp. Two-dimensional electrophoresis (2D-PAGE) showed a higher number of protein-derived major spots in aHAp (37 spots) than in iHAp (12 spots). Mass spectrometry analysis of the resulting 2D-PAGE gels revealed proteins adsorbed on aHAp, including secreted frizzled-related protein 3 and vitamin K epoxide reductase complex 1, which are involved in cellular bone differentiation. Overall, these proteins are expected to promote bone differentiation, representing a characteristic property of aHAp.

Preparation of Biomass Biochar with Components of Similar Proportions and Its Methylene Blue Adsorption.

Rapeseed straw, bagasse, and walnut peel have a large amount of resource reserves, but there are few technologies for high value-added utilization. In the research of biochar, walnut green husk is rarely used as raw material. In addition, the three main components of biomass (lignin, cellulose, and hemicellulose) are present in similar proportions, and the differences between the physical and chemical properties of biochar prepared with similar amounts of biomass raw materials are not clear. Using three kinds of biomass of the same quality as raw materials, biochar was prepared via pyrolysis at 400 °C, and activated carbon was prepared via CO2 activation at 800 °C. The results showed that the pore numbers of the three kinds of biochar increased after activation, resulting in the increase of the specific surface area. The resulting numbers were 352.99 m2/g for sugarcane bagasse biochar (SBB)-CO2, 215.04 m2/g for rapeseed straw biochar (RSB)-CO2, and 15.53 m2/g for walnut green husk biochar (WGB)-CO2. Ash increased the amount of carbon formation, but a large amount of ash caused biochar to form a perforated structure and decreased the specific surface area (e.g., WGB), which affected adsorption ability. When the three main components were present in similar proportions, a high content of cellulose and lignin was beneficial to the preparation of biochar. The adsorption value of MB by biochar decreased with the increase of biomass ash content. After activation, the maximum adsorption value of MB for bagasse biochar was 178.17 mg/g, rapeseed straw biochar was 119.25 mg/g, and walnut peel biochar was 85.92 mg/g when the concentration of methene blue solution was 300 mg/L and the biochar input was 0.1 g/100 mL at room temperature. The adsorption of MB by biochar in solution occurs simultaneously with physical adsorption and chemical adsorption, with chemical adsorption being dominant. The optimal MB adsorption by SBB-CO2 was dominated by multimolecular-layer adsorption. This experiment provides a theoretical basis for the preparation of biochar and research on its applications in the future.

A promising sensing platform for explosive markers: Zeolite-like metal-organic framework based monolithic composite as a case study

Preconcentration for on-site detection or subsequent determination is a promising technique for selective sensing explosive markers at low concentrations. Here, we report divinylbenzene monolithic polymer in its blank form (neat-DVB) and as a composite incorporated with sodalite topology zeolite-like metal-organic frameworks (3-ZMOF@DVB), as a sensitive, selective, and cost-effective porous preconcentrator for aliphatic nitroalkanes in the vapor phase as explosive markers at infinite dilution. The developed materials were fabricated as 18 cm gas chromatography (GC) monolithic capillary columns to study their separation performance of nitroalkane mixture and the subsequent physicochemical study of adsorption using the inverse gas chromatography (IGC) technique. A strong preconcentration effect was indicated by a specific retention volume adsorption/desorption ratio equal to 3 for nitromethane on the neat-DVB monolith host-guest interaction, and a 14% higher ratio was observed using the 3-ZMOF@DVB monolithic composite despite the low percentage of 0.7 wt.% of sod-ZMOF added. Furthermore, Incorporating ZMOF resulted in a higher percentage of micropores, increasing the degree of freedom more than bringing stronger adsorption and entropic-driven interaction more than enthalpic. The specific free energy of adsorption (ΔGS) values increased for polar probes and nitroalkanes, denoting that adding ZMOFs earned the DVB monolithic matrix a more specific character. Afterward, Lewis acid-base properties were calculated, estimating the electron acceptor (KA) and electron donor (KB) constants. The neat-DVB was found to have a Lewis basic character with KB/KA = 7.71, and the 3-ZMOF@DVB had a less Lewis basic character with KB/KA = 3.82. An increased electron-accepting nature can be directly related to incorporating sod-ZMOF into the DVB monolithic matrix. This work considers the initial step in presenting a portable explosives detector or preconcentrating explosive markers trace prior to more sophisticated analysis. Additionally, the IGC technique allows for understanding the factors that led to the superior adsorption of nitroalkanes for the developed materials.

The synergistic effects of cationic surfactant and smart seawater on the recovery of medium-viscosity crude oil from low-permeability carbonates

In the petroleum industry, there is a continuous search for cost-effective enhanced oil recovery (EOR) methods to increase oil extraction. Surfactant-based EOR is one of these effective methods, which is applied after the primary and secondary recovery phases. This paper presents an experimental study on the use of a cationic surfactant, hexadecyltrimethylammonium bromide (CTAB, CH3(CH2)15N(Br)(CH3)3), and smart seawater (SW) for EOR in low-permeability carbonate rock with medium viscosity crude oil. Smart SW was prepared by modifying the concentrations of Ca2+, Mg2+, and SO42- in synthetic offshore SW. The aqueous stability of CTAB was tested in different salinities of smart SW at the reservoir temperature. It was demonstrated that CTAB is stable at 55 °C, which was further confirmed through optical transmittance measurements, revealing values mostly exceeding 93%. The use of smart SW and CTAB significantly altered the wettability of carbonate rock towards water-wet and reduced the interfacial tension (IFT) between crude oil and water, reaching levels below 0.087 mN/m. However, the presence of smart SW increased the adsorption of CTAB onto the surface of carbonate rock. Nevertheless, the adsorption values were significantly below 1 mg/g-rock. Smart SW + CTAB resulted in a total oil recovery of 76.71% of original oil-in-place (OOIP), compared to 71.70% of OOIP with unmodified SW + CTAB. These results suggest that the use of smart SW in combination with CTAB is a promising approach for enhancing the recovery of medium-viscosity oil from tight carbonate reservoirs. Findings from this study can help in better understanding the optimal conditions for the application of smart SW-CTAB flooding to improve the effectiveness of tertiary recovery operations in the upstream oil sector.

Tuning the magnetic properties of nonmagnetic monolayer Mo2C by doping and adsorption

For purpose of probing doping and adsorption induced ferromagnetism in nonmagnetic behavior of Mo2C monolayer, the electronic and magnetic properties of a transition metal atom (TM = V, Cr, Mn, Fe, Co, Ni) doped/adsorbed in/on Mo2C monolayer are researched by first principles methods. Firstly, both pristine and TM-doped/adsorbed in/on Mo2C monolayer show the metallic character. For Mn/Co-doped Mo2C monolayer, they present ferromagnetism with the total magnetic moments of 0.656 μB and 0.722 μB, which mainly come from the 3d electrons of Mn and Co sites. Moreover, the Cr/Mn/Fe/Co atom adsorption on Mo2C monolayer exhibit spin-polarized character. The exchange splitting in the d shell is discovered in Cr/Mn/Fe/Co-adsorbed onto monolayer Mo2C. Finally, the positive value of MAE for Co-doped and Cr/Mn/Co-adsorbed Mo2C systems indicates an out-of-plane easy axis, whereas the negative MAE value for Mn-doped Mo2C monolayer and Fe adsorption on Mo2C monolayer implies the easy axis in the surface.

Performance of Thermal-, Acid-, and Mechanochemical-Activated Montmorillonite for Environmental Protection from Radionuclides U(VI) and Sr(II)

Low-cost sorption materials based on the clay mineral of the smectite group—montmorillonite—were used for the removal of radionuclides uranium (VI) and strontium (II) from contaminated water. A wide range of industrial methods such as thermal treatment, acid activation, and mechanochemical activation were applied. Complex methods, such as SEM microscopy analysis, X-ray powder diffraction (XRD), thermal analysis, and nitrogen adsorption–desorption at −196 °C, were used to assess the characteristics of the structure of the obtained materials. The thermal treatment, acid activation, and mechanochemical activation resulted in changes in the surface properties of the clay minerals: specific surface area, porosity, and distribution of active sites. It was established that the mechanochemical activation of montmorillonite significantly increases the sorption characteristics of the material for U(VI) and Sr(II) and the acid activation of montmorillonite increases it for U(VI). The appropriateness of the experimental adsorption values for U(VI) and Sr(II) on modified montmorillonite to Langmuir and Freundlich models was found. Independently of the changes induced by acid attack, calcinations, or milling, the sorption of U(VI) and Sr(II) ions on treated montmorillonite occurs on a homogeneous surface through monolayer adsorption in a similar fashion to natural montmorillonite. Water purification technologies and modern environmental protection technologies may successfully use the obtained clay-based sorbents.

Техногенная нагрузка на водные ресурсы угледобывающих регионов

The state of Kuzbass water resources is attracting more and more attention, which is associated with increasing industrial use. The risk of reducing the sanitary reliability of water bodies is due to an increase in the amount of industrial wastewater and the multicomponent nature of their composition. For Kuzbass as a coal-mining region, wastewater treatment of coal mining and processing enterprises is relevant. The data of monitoring reporting, the characteristics of the applied cleaning methods are given in the paper. The most common system of treatment facilities in coal mines, the formation of runoff and problem areas are considered. The sewage receiver is small rivers, the layers are drained by natural drainage, the drainage water is collected in sumps, then it is pumped to the settling ponds by pumps. In the settling ponds, wastewater stays for several days, which leads to the release of suspended particles. After the dam, the treated wastewater is divided into two streams: one is discharged into a reservoir, the other is sent to a storage pond to use this water in the technological process. The possibility of using filtration through artificial filter arrays with a layer consisting of a carbon sorbent at the second stage of purification was studied. The filtering carbon material based on anthracite — Purolat-Standard and coconut charcoal, the raw material for which is a natural material, are analyzed. Adsorption isotherms were used as a criterion for evaluating the adsorption capacity of materials. The sorption capacity of coconut charcoal with respect to iron ions when extracted from individual model solutions, according to the experiment, was 0.54 mg/g. The content of manganese in the solution after adsorption on coconut charcoal decreased according to the experimental data, and the adsorption value was 147 mg/g.

Full-value preparation of biochar and 2D N-doped CDs@ZIF-L from fermentation residues for sensitive sensing tetracyclines in food samples

The use of thermal conversion to convert Chinese patent medicines (CPM) residues into porous carbon-based materials and carbon dots (CDs) has effectively resolved the challenges associated with resource waste and environmental pollution while enhancing the added value of CPM residues. In this study, biochar and N-doped CDs with high quantum yield (QY) were simultaneously prepared from fermentation residues by employing a hydrothermal carbonization method without any chemical reagents. The obtained biochar had remarkable adsorption capacity, with an iodine adsorption value of 693.22 mg g–1. The QY of N-doped CDs could reach to 36.17 % by the mean of self-doping due to the high nitrogen content of the fermentation residues. Considering the structural integrity and permeable porous structure of the two-dimensional leaf-like zeolitic imidazole framework (ZIF-L), N-doped CDs were encapsulated into ZIF-L to form novel fluorescent composites (N-doped CDs@ZIF-L). Moreover, N-doped CDs@ZIF-L as a novel fluorescent probe could be efficiently quenched in the presence of tetracycline (TC), doxycycline (DOC), and chlortetracycline (CTC) by static quenching and the inner filter effect. Notably, the fluorescent probe exhibited a good linear relationship with the TC, DOC, and CTC at 0–50, 0–50, and 0–45 μM, respectively, with limits of detection of 0.025, 0.033, and 0.027 μM, respectively. This probe could be employed to detect TC antibiotics in honey and milk, suggesting that it had the great potential for applications in environmental monitoring and food safety.

Differences in the distribution, availability, and sorption-desorption isotherms of phosphorus fractions in soil aggregates from cut slopes with different restoration methods

The construction of highways and other transportation facilities resulted in a large number of exposed cut slopes, leading not only to the alteration of soil structure but also to phosphorus (P) losses from soils with low utilization rates. These negative effects can result in stunted plant growth and the occurrence of heavy rainfall and earthquakes-associated landslide and mudslide disasters, threatening people's lives. However, few studies have investigated soil aggregates P in cut slopes restored with different methods in the Alpine Mountainous areas of Southwest China. Therefore, three types of cut slopes (cut slopes restored by three-dimensional mesh (TCS), cut slopes restored by galvanized wire mesh (GCS), and cut slopes restored by nature (NCS)) were selected for the study, and the present study aims to assess the total phosphorus (TP), available phosphorus (AP), and P fractions, as well as the P sorption-desorption isotherms in cut slope soil aggregates. The obtained results are as follows: (1) The TP contents in the soil aggregates did not differ significantly between the three types of cut slopes (p > 0.05), In addition, the AP contents and P activation coefficient (PAC) showed significant differences between TCS, GCS, and NCS, while the H2O-Pi, NaHCO3-Po, NaOH-Pi, NaOH-Po, HHCl-Pi, and HHCl-Po contents were significantly different between the three types of cut slopes (p < 0.05); (2) The AP contents in the three types of cut slopes showed a decreasing trend with increasing soil aggregate size from < 0.25 mm to > 5 mm; (3) H2O-Pi, NaOH-Pi, and HHCl-Pi were the main P fractions affecting the AP contents in the study area, among which NaOH-Pi exhibited the greatest effect on the AP contents; (4) The lowest P adsorption of soil aggregates was observed in NCS. The maximum P adsorption (Qm) values of the < 0.25 mm aggregates in TCS and GCS were higher than those of the other soil aggregate sizes. In addition, the trend of P desorption to increase with P adsorption was more obvious in large aggregates than in small aggregates. The present study provides a theoretical basis for P management in cut slope soils restored by different methods in the Alpine Mountainous region of Southwest China. Moreover, it provides some references for improving cut slope restoration and ecological slope protection techniques.

Enhanced Degradation of Methyl Orange and Trichloroethylene with PNIPAm-PMMA-Fe/Pd-Functionalized Hollow Fiber Membranes.

Trichloroethylene (TCE) is a prominent groundwater pollutant due to its stability, widespread contamination, and negative health effects upon human exposure; thus, an immense need exists for enhanced environmental remediation techniques. Temperature-responsive domains and catalyst incorporation in membrane domains bring significant advantages for toxic organic decontamination. In this study, hollow fiber membranes (HFMs) were functionalized with stimuli-responsive poly-N-isopropylacrylamide (PNIPAm), poly-methyl methacrylate (PMMA), and catalytic zero-valent iron/palladium (Fe/Pd) for heightened reductive degradation of such pollutants, utilizing methyl orange (MO) as a model compound. By utilizing PNIPAm's transition from hydrophilic to hydrophobic expression above the LCST of 32 °C, increased pollutant diffusion and adsorption to the catalyst active sites were achieved. PNIPAm-PMMA hydrogels exhibited 11.5× and 10.8× higher equilibrium adsorption values for MO and TCE, respectively, when transitioning from 23 °C to 40 °C. With dip-coated PNIPAm-PMMA-functionalized HFMs (weight gain: ~15%) containing Fe/Pd nanoparticles (dp~34.8 nm), surface area-normalized rate constants for batch degradation were determined, resulting in a 30% and 420% increase in degradation efficiency above 32 °C for MO and TCE, respectively, due to enhanced sorption on the hydrophobic PNIPAm domain. Overall, with functionalized membranes containing superior surface area-to-volume ratios and enhanced sorption sites, efficient treatment of high-volume contaminated water can be achieved.

Comparative study of influence of molecular structure of hydrogenocarbonate contaminants in adsorption process, using cactus pear forage (Opuntia fícus) as biomass

This work used adsorption technique to evaluate adsorption efficiency of an easily accessible biomass in Paraiba, cactus pear forage (Opuntia fícus), to remove organic contaminants from water/lubricating oil and water/diesel oil systems present in water bodies. Study was developed to obtain kinetic curves to characterization of adsorption dynamics of lubricating oil and diesel oil in contact with biomass. For this, methodology described by Lima et al. (2014), which used mandacaru biomass (Cereus jamacaruna) in particulate form to remove gasoline/diesel mixture, which consisted of: preparing biomass on particulate form, for further granulometric analysis, using sieves; conducting experiments to investigate adsorption kinetics and to obtain adsorption isotherms to complementation of equilibrium study. In despite low adsorption values confirmed by kinetics and equilibrium adsorption graphs, at some points 50% of adsorbed lubricating oil was obtained, which may characterize cactus pear forage as a relatively efficient adsorbent. Low values obtained on adsorption of diesel oil may have been influenced by molecular structure of diesel, constituted of long chains that may have favored oscillations on adsorption by means of cactus pear forage biomass.

Investigation of adsorption equilibrium in the system of ammonium ions and a calcined sorbent from ash and slag waste of thermal power plants

A calcined sorbent from ash and slag waste of thermal power plants was used for water purification from ammonium ions. Experiments were carried out under static conditions at a temperature of 25±2 °С. The concentration of ammonium ions in the solution was measured by the spectrophotometric method according to the established graduation characteristic tested for convergence and correctness. The sorption process was studied at a sorbent dose of 1.0 g per 50 cm3 of the model solution taking the specific pore volume of the sorbent into account. For a solution with an ammonium ion content of 20 mg/dm3, the following modifications were carried out: the frequency of magnetic stirrer rotation was varied from 50 to 500 rpm; the pH of the solution – from 4 to 9; and the time to equilibrium – from 10 to 210 min. The time to equilibrium was 180 min. The effect of initial concentration of ammonium ions (2.0; 5.0; 20; 50 and 100 mg/dm3) in the solution on the adsorption process was studied under optimal sorption parameters. The adsorption equilibrium in the “ammonium ions–calcined sorbent” system was studied for the initial concentration of ammonium ions from 5 to 300 mg/dm3. Experimental data were processed using Langmuir and Freundlich adsorption isotherms. The maximum value of adsorption comprised 1.1251 mg/g. The experimental data were found to agree with the Langmuir theory. To describe the adsorption kinetics, the parameters of pseudo-first and pseudo-second order equations were determined. The highest convergence between the experimental and calculated data was achieved by the pseudo-first order model.

Effect of Levels of Organic Matter on Adsorption and Liberation of Gypsum Soil

In an experiment for iron adsorption for nine levels of iron (0,1,2,5,10,25,50,100,200)mg/L. This experiment was carried out to find the behaviour of iron in soils of varying gypsum and organic content to know the conditions for adsorption and liberation of iron in them, using three gypsums (10,20,30)% with percentages of organic matter from sheep feces (0,1,2)%. The Langmeyer equation, the Feinrendlach equation, and the Timken equation were used, through which the most excellent adsorption and binding energy were calculated. The most outstanding adsorption values were In medium gypsum soil with sheep feces (2%) with a ratio in the Langmeyer equation (46.948) mg/kg. The highest binding energy value was (7.497) L.mg-1 in soils with low gypsum content as a control. Lanckmeyer equation was chosen as the best It is fair to describe the adsorption process with a capacity determination coefficient of (85)%. In comparison, the highest value for the maximum adsorption of the Freindlch equation was recorded (0.788) litre.mg-1 in soils with high gypsum content with sheep feces by (2%). The highest percentage of binding energy in medium soils, gypsum control, was (16.195) mg.kg-1. The highest binding energy value in the Tamken equation was (12.436) mg.kg-1 in medium gypsum control soil. The highest binding energy value was (2.844) L.kg-1 in medium gypsum soil control. As for the liberation experiment, the highest values for liberated iron were in the high levels of addition (18.513) mg.kg-1 in soils with low gypsum content (2)% of sheep feces, noting the low values Released iron with low values of adsorbed iron.

A Symmetry Concept for the Self-Assembly Synthesis of Mn-MIL-100 Using a Capping Agent and Its Adsorption Performance with Methylene Blue

In this study, a facile strategy of regulated self-assembly synthesis of Mn-MIL-100, using sodium acetate (CH3COONa) as a mono-dentate ligand capping agent (CA), was proposed. The as-prepared product is denoted Mn-MIL-100-CA. The coordination modulation of CH3COONa, led by its interference in the connectivity and symmetry of the metal centers and organic nodes, plays a vital role in the synthesis process. The crystallinity, morphology, topology, and properties of such MOF products were improved, since the self-assembly process of Mn-MIL-100-CA was promoted and regulated effectively. The materials were systematically characterized via XRD, SEM, N2 isotherms, XPS, and TGA in terms of crystallization behavior, morphology, topology, chemical composition, and thermal and water stability. The ability of Mn-MIL-100 and Mn-MIL-100-CA to remove methylene blue (MB) from an aqueous solution was investigated using a UV–vis spectrophotometer. The results indicate that with the addition of a molar ratio of 50% CH3COONa, Mn-MIL-100-CA particles developed a regularly symmetrical morphology, i.e., ‘spherical pyramid-like structure’ crystals with a dimension of 2~5 μm. Their specific surface area and pore volume increased by 59.2% and 56.7%, respectively. The increased proportion of Mn3+ implies reduced crystal defects and improved crystal structural order and integrity, and therefore an enhanced water stability. Mn-MIL-100-CA exhibited excellent adsorption performance towards MB from aqueous solution. The equilibrium adsorption value was as high as 1079.9 mg/g, which is 44.7% higher than that of Mn-MIL-100 without the addition of CA. The good adsorption capacity and excellent water stability mean that Mn-MIL-100-CA has great potential for the practical removal of MB dye pollutants from water.

Effect of litho-facies on nano-pore structure of continental shale in shuinan formation of Jiaolai Basin

Continental shale lithofacies has an important influence on nano-pore structure? However, nano-pore distribution heterogeneity (NDH) in continental shale lithofacies is not well documented. Continental shale was collected from the Shuinan Formation in the Jiaolai Basin, and the shale lithofacies of all samples are identified based on the mineralogical composition and TOC content. Nano-pore size distributions are characterized by LPN2 and CO2GA tests. Then, micro-pore (0.3∼2 nm) and meso-pore (2∼100 nm) distribution heterogeneity of different facies are discussed by single and multi-fractal model. Finally, the pore structure mechanism in shale lithofacies is clarified, and the results are as follows. The lithofacies of all shale samples are classified into three types, (A) calcareous shale lithofacies is characterized by the higher siliceous minerals and highest TOC content; (B) Calcareous/siliceous mixed shale lithofacies is characterized by middle TOC content; (C) Siliceous shale lithofacies is characterized by higher clay minerals and lowest TOC content. Micro- and meso-pore volume and A shale lithofacies NDH is much lower than that of B and C, which indicates that the lithofacies type has a great influence on the nano-pore structure. Felsic mineral and TOC content has a weak negative correlation with nano-pore structure, and there is a linear relationship between clay mineral content and nano-pore volume, indicating that clay mineral content is the main factor that can affect nano-pore structure. Moreover, fractal characteristics of the nitrogen desorption curve have been proved, and there are obvious differences in the fractal values of adsorption and desorption curves among those different lithofacies. Single fractal dimension D1 derived from LPN2 and CO2GA tests has a linear correlation with the multifractal parameter D-10-D0, which shows that a lower pore volume of pore diameter determines NDH variation. In conclusion, siliceous rich shale can provide a larger pore volume and specific surface area, and it acts as the dominant lithofacies for shale gas drainage in the study area.

Photocatalytic Removal of Water Emerging Pollutants in an Optimized Packed Bed Photoreactor Using Solar Light

Photocatalysis is an advanced oxidation process that is an environmentally friendly option and one of the most critical technologies in green chemistry today. This work studied the upscaling of photocatalysis as a suitable process for wastewater treatment to remove emerging pollutants. For this purpose, unsupported and supported TiO2 photocatalysts were tested in the photodegradation of ciprofloxacin as a model molecule of an emerging wastewater component, using visible, UV radiation, and solar light. The suitability of TiO2 as a photocatalyst to decompose ciprofloxacin was confirmed in batch photoreactor under Visible and UV radiation, with degradation rates up to 90% after 30 min of irradiation and low adsorption values. TiO2 as a photocatalyst coated in glass support material at the packed bed photoreactor showed good photoactivity for emergent contaminants degradation (95%) under solar radiation. It has been possible to verify that the photocatalytic reactor system constitutes a viable process for eliminating emerging contaminants through environmentally sustainable treatments. Our results corroborate the possibility of degrading emerging contaminants by solar radiation using a packed bed photoreactor, providing a more effective option from a practical and economical point of view for wastewater effluent treatments.

Gasoil removal from aqueous solution using magnetic metal-organic framework adsorbent based on the cellulosic fibrous of Prosopis farcta plant

Recently, the leakage of Gasoil and other petroleum substances into the seas, surface water, and wastewater has become a global problem; therefore, providing a solution to remove these pollutants seems vital. In the current research, we investigated the removal of floating Gasoil from aqueous solutions. First, the magnetic metal-organic framework was prepared as a new adsorbent based on the cellulosic fibrous of the Prosopis farcta plant (magnetic- cellulose@MIL-53(Fe) carbon aerogel). Using design of experiment, the effect of parameters pH, Gasoil concentration, and adsorbent weight on Gasoil removal were investigated. The adsorbent prepared under optimal parameters can remove 100% floating Gasoil from the aqueous solution. The adsorption capacity of the magnetic- cellulose@MIL-53 (Fe) carbon aerogel is 7.48 g.g−1, which is almost 100 times more than other Fe-based adsorbents. The study of the effect of time showed that the adsorption of Gasoil by the adsorbent is not dependent on time. Gasoil adsorption on magnetic- cellulose@MIL-53(Fe) carbon aerogel follows the Freundlich isotherm with a correlation coefficient of 0.9933. Thermodynamic factors Gibbs free energy, enthalpy, and entropy changes have been calculated. Accordingly, magnetic- cellulose @MIL-53(Fe) carbon aerogel has rapid separation and high stability, and it could be used as a good adsorbent to remove Gasoil from an aqueous solution. With good cycling stability of 86% retention of the initial adsorption value after ten adsorption/desorption cycles.

Synthesis and properties of Gemini surfactant based on dodecyldiethylolammonium, dodecyltriethylolammonum bromide and potassium oxalate

The article focuses on the synthesis of Gemini cationic surfactants using dodecyldiethylolammonium bromide (DDDEAB), dodecyltriethylolammonium bromide (DDTEAB) and 2:1 mol potassium oxalate (PO). The structure of the obtained substances was determined using IR-spectroscopy. The study examines the surface tension and electrical conductivity of the new surfactants in aqueous solutions with different concentrations. The parameters such as critical micelle concentration, degree of counterion binding, effectiveness of surface tension reduction, surface excess concentration, surface area polar group per molecule at the air-water interface, Gibbs free energy values of adsorption and micellar formation processes were calculated. The article investigates the petroleum collecting and dispersing properties as well. Collecting and dispersing ability of the surfactants on a petroleum sample from Pirallahi field under laboratory conditions were observed.