Green synthesis of silver and iron nano composites using aqueous extract of zanthoxylum armatum seeds and their application for removal of acid black 234 dye.

Green nanotechnology has gained attraction in recent years due to the growing awareness of the environmental and health risks associated with traditional methods of nanomaterial synthesis. In the present study, nanocomposite (NCs) of silver and Iron were prepared using Zanthoxylum Armatum seeds aqueous extract which acts as a reducing, stabilizing, and capping agent. The synthesized NCs were characterized using UV/Vis Spectroscopy, powder X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and EDX. The UV/Vis spectroscopy analysis of the NCs revealed the presence of a surface plasmonic resonance band occurring at 420 nm. Examination of the NCs through SEM demonstrated that they exhibited a nearly spherical morphology, with an average particle diameter measuring 54.8 nm. The crystalline nature of these NCs was verified through X-ray diffraction (XRD), and the calculation of crystallite size using the Scherrer-Debye equation yielded a value of 12.6 nm. The adsorption ability of newly synthesized nanocomposites was investigated against Acid Black 234 Dye. The results showed that a 0.5 g of NCs dose at pH 4 removed 99.3% of 10 mg/L of Acid Black 234 Dye within 60 min. Based on the findings of this research, it can be inferred that the that Ag-Fe NCs synthesized from Zanthoxylum Armatum seeds aqueous extract hold significant potential for addressing environmental pollution caused by Acid Black 234 Dye. The NCs were used as adsorbent for the removal of Acid Black 234 dye from the wastewater sample and showed 98% removal of dye from the commercial sample within 60 min. In this context, the research highlights that the environmentally friendly synthesis of Ag-Fe nanocrystals (Ag-Fe NCs) using Zanthoxylum Armatum as a mediator offers an efficient and cost-effective solution for mitigating environmental pollution.

Enabling High Reversibility of Zn anode via Interfacial Engineering Induced by Amino acid Electrolyte Additive.

Despite possessing substantial benefits of enhanced safety and cost-effectiveness, the aqueous zinc ion batteries (AZIBs) still suffers with the critical challenges induced by inherent instability of Zn metal in aqueous electrolytes. Zn dendrites, surface passivation, and corrosion are some of the key challenges governed by water-driven side reactions in Zn anodes. Herein, a highly reversible Zn anode is demonstrated via interfacial engineering of Zn/electrolyte driven by amino acid D-Phenylalanine (DPA) additions. The preferential adsorption of DPA and the development of compact SEI on the Zn anode suppressed the side reactions, leading to controlled and uniform Zn deposition. As a result, DPA added aqueous electrolyte stabilized Zn anode under severe test environments of 20.0 mA cm-2 and 10.0 mAh cm-2 along with an average plating/stripping Coulombic efficiency of 99.37%. Under multiple testing conditions, the DPA-incorporated electrolyte outperforms the control group electrolyte, revealing the critical additive impact on Zn anode stability. This study advances interfacial engineering through versatile electrolyte additive(s) toward development of stable Zn anode, which may lead to its practical implementation in aqueous rechargeable zinc batteries.

Norfloxacin adsorption by urban green waste biochar: characterization, kinetics, and mechanisms.

Biochar, as a potential adsorbent, has been widely employed to remove pollutants from sewage. In this study, a lignin-based biochar (CB-800) was prepared by a simple high-temperature pyrolysis using urban green waste (Cinnamomum camphora leaves) as a feedstock to remove norfloxacin (NOR) from water. Batch adsorption test results indicated that CB-800 had a strong removal capacity for NOR at a wide range of pH values. The maximum adsorption achieved in the study was 50.90 ± 0.64 mg/g at 298 K. The pseudo-first and second-order kinetic models and the Dubinin-Radushkevich isotherm fitted the experimental data well, indicating that NOR adsorption by CB-800 was a complex process involving both physi-sorption and chemi-sorption. The physical properties of CB-800 were characterized by SEM and BET. The mesoporous structures were formed hierarchically on the surface of CB-800 (with an average pore size of 2.760 nm), and the spatial structure of NOR molecules was more easily adsorbed by mesoporous structures. Combined with Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis, it was showed that the main NOR adsorption mechanisms by CB-800 included ion exchange, π-electron coordination, hydrogen bonding, and electrostatic adsorption. Meanwhile, the reduction of C = O and pyridine nitrogen, and the presence of C-F2, also indicated the occurrence of substitution, addition, and redox. This study not only determined the reaction mechanism between biochar and NOR, but also provides guidance to waste managers for the removal of NOR from water by biochar. It is envisaged that the results will broaden the utilization of urban green waste.

Efficient phosphate removal by Mg-La binary layered double hydroxides: synthesis optimization, adsorption performance, and inner mechanism.

Layered double hydroxides (LDH) hold great promise as phosphate adsorbents; however, the conventional binary LDH exhibits low adsorption rate and adsorption capacity. In this study, Mg and La were chosen as binary metals in the synthesis of Mg-La LDH to enhance phosphate efficient adsorption. Different molar ratios of Mg to La (2:1, 3:1, and 4:1) were investigated to further enhance P adsorption. The best performing Mg-La LDH, with Mg to La ratio is 4:1 (LDH-4), presented a larger adsorption capacity and faster adsorption rate than other Mg-La LDH. The maximum adsorption capacity (87.23 mg/g) and the rapid adsorption rate in the initial 25 min of LDH-4 (70 mg/(g·h)) were at least 1.6 times and 1.8 times higher than the others. The kinetics, isotherms, the effect of initial pH and co-existing anions, and the adsorption-desorption cycle experiment were studied. The batch experiment results proved that the chemisorption progress occurred on the single-layered LDH surface and the optimized LDH exhibited strong anti-interference capability. Furthermore, the structural characteristics and adsorption mechanism were further investigated by SEM, BET, FTIR, XRD, and XPS. The characterization results showed that the different metal ratios could lead to changes in the metal hydroxide layer and the main ions inside. At lower Mg/La ratios, distortion occurred in the hydroxide layer, resulting in lower crystallinity and lower performance. The characterization results also proved that the main mechanisms of phosphate adsorption are electrostatic adsorption, ion exchange, and inner-sphere complexation. The results emphasized that the Mg-La LDH was efficient in phosphate removal and could be successfully used for this purpose.

A novel ionic liquid-entrapped MIL-101(Cr) framework with enhanced removal efficiency towards phosphate from aqueous solution.

Developing adsorbent materials with high adsorptive dephosphorization (ADP) is significant for treating phosphate from aqueous solutions and eutrophic water. Herein, the MIL-101(Cr) framework was entrapped ionic liquid (IL) of 1-butyl-3-methylimidazoliumbromide ionic liquid ([C4mem]+[Br]-) using a ship-in-a-bottle approach to obtain novel adsorbents [C4mem]+[Br]-@MIL-101(Cr) contained varied IL contents, namely C4mem@MIL-101. The characterization results revealed that the formed [C4mem]+[Br]- molecules interacted with the MIL-101(Cr) frameworks, enhanced their stability, and offered additional adsorption sites. The batch adsorptions of phosphate showed that the optimized C4mem@MIL-101 adsorbent loaded with ~ 7% IL-based N content had the highest phosphate absorbing capacity of ~ 200 mg/g, outperforming the pristine MIL-101(Cr) and other adsorbents. The ADP efficiency was facilitated in the acidic media, where the phosphate ions of H2PO4- and HPO42- captured onto the C4mem@MIL-101 via several interactions, including electrostatic attraction, H-bonds, and chemical interactions. In the meantime, the coexisting anions diminished the phosphate adsorption because they competed with the pollutants at adsorption sites. Furthermore, phosphate treatment under the continuous fixed-bed conditions showed that 1 g of the polyvinyl alcohol (PVA)-mixed C4mem@MIL-101 pellets purified 25 l of water containing phosphate with a 1 mg/l concentration. The results suggest that the novel [C4mem]+[Br]-@MIL-101(Cr) structure had a high potential for treating phosphate in aqueous solutions.

Integration of adsorption, reduction, and filtration in PANI/PVDF nanofiber composite membrane for removal of Cr(VI).

Here, polyaniline/polyvinylidene fluoride (PANI/PVDF) nanofiber composite membrane was fabricated using electrostatic spinning technology to remove hexavalent chromium Cr(VI). The employment of PANI not only extremely enhanced the hydrophilic property of the nanofiber membrane, but also facilitated the transfer of Cr2O72- from water to the membrane. The PANI/PVDF membrane had an extremely excellent performance in getting rid of Cr(VI) and a quite large flux (250 L/m2 h). The maximum adsorption quantity of the membrane could reach 334.5 mg/g in which adsorption played 52.12% part and reduction played 47.87% part. The removal rate could reach nearly 100% immediately in the permeate solution under filtration while it needed 240 min to reach 100% only by static adsorption. Therefore, the interception of the membrane and the adsorption reduction of PANI had synergistic effect on removal of Cr(VI). Furthermore, the removal rate of Cr(VI) could still reach 95.97% after reused 8 times. The membrane showed a very good reusability and application prospect.

Sustainable efficient utilization of magnetic porous biochar for adsorption of orange G and tetracycline: Inherent roles of adsorption and mechanisms.

Iron-doped biochar has been widely used as an adsorbent to remove contaminants due to the high adsorption performance, but it still suffers from complicated preparation methods, unstable iron loading, unsatisfactory specific surface area, and uneven distribution of active sites. Here, a novel magnetic porous biochar (FeCS800) with nanostructure on surface was synthesized by one-pot pyrolysis method of corn straw with K2FeO4, and used in orange G (OG) and tetracycline (TC) adsorption. FeCS800 exhibited outstanding adsorption capacities for OG and TC after K2FeO4 activation and the adsorption data were fitted satisfactorily to Langmuir isotherm and Pseudo-second-order kinetic model. The maximum adsorption capacities of FeCS800 for OG and TC were around 303.03 mg/g and 322.58 mg/g, respectively, at 25 °C and pH 7.0, which were 16.27 and 24.61 times higher than that before modification. Thermodynamic studies showed that the adsorption of OG/TC by FeCS800 were thermodynamically favorable and highly spontaneous. And the adsorption capacity of OG and TC by FeCS800 remained 77% and 81% after 5 cycles, respectively, indicating that FeCS800 had good stability. The outstanding adsorption properties and remarkable reusability of FeCS800 show its great potential to be an economic and environmental adsorbent in contaminants removal.

Adsorption properties and mechanism of Cu(II) on virgin and aged microplastics in the aquatic environment.

Microplastics (MPs) migrate by adsorbing heavy metals in aquatic environments and act as their carriers. However, the aging mechanisms of MPs in the environment and the interactions between MPs and heavy metals in aquatic environments require further study. In this study, two kinds of materials, polyamide (PA) and polylactic acid (PLA) were used as target MPs, and the effects of UV irradiation on the physical and chemical properties of the MPs and the adsorption behavior of Cu(II) were investigated. The results showed that after UV irradiation, pits, folds and pores appeared on the surface of aged MPs, the specific surface area (SSA) increased, the content of oxygen-containing functional groups increased, and the crystallinity decreased. These changes enhanced the adsorption capacity of aged MPs for Cu(II) pollutants. The adsorption behavior of the PA and PLA MPs for Cu(II) conformed to the pseudo-second-order model and Langmuir isotherm model, indicating that the monolayer chemical adsorption was dominant. The maximum amounts of aged PA and PLA reached 1.415 and 1.398 mg/g, respectively, which were 1.59 and 1.76 times of virgin MPs, respectively. The effects of pH and salinity on the adsorption of Cu(II) by the MPs were significant. Moreover, factors such as pH, salinity and dosage had significant effects on the adsorption of Cu(II) by MPs. Oxidative complexation between the oxygen-containing groups of the MPs and Cu(II) is an important adsorption mechanism. These findings reveal that the UV irradiation aging of MPs can enhance the adsorption of Cu(II) and increase their role as pollutant carriers, which is crucial for assessing the ecological risk of MPs and heavy metals coexisting in aquatic environments.

Amino-functionalized novel biosorbent for effective removal of fluoride from water: process optimization using artificial neural network and mechanistic insights.

Aqueous fluoride ( F - ) pollution is a global threat to potable water security. The present research envisions the development of novel adsorbents from indigenous Limonia acidissima L. (fruit pericarp) for effective aqueous defluoridation. The adsorbents were characterized using instrumental analysis, e.g., TGA-DTA, ATR-FTIR, SEM-EDS, and XRD. The batch-mode study was performed to investigate the influence of experimental variables. The artificial neural network (ANN) model was employed to validate the adsorption. The dataset was fed to a backpropagation learning algorithm of the ANN (BPNN) architecture. The four-ten-one neural network model was considered to be functioning correctly with an absolute-relative-percentage error of 0.633 throughout the learning period. The results easily fit the linearly transformed Langmuir isotherm model with a correlation coefficient ( R 2 ) > 0.997. The maximum F - removal efficiency was found to be 80.8 mg/g at the optimum experimental condition of pH 7 and a dosage of 6 g/L at 30 min. The ANN model and experimental data provided a high degree of correlation ( R 2 = 0.9964), signifying the accuracy of the model in validating the adsorption experiments. The effects of interfering ions were studied with real F - water. The pseudo-second-order kinetic model showed a good fit to the equilibrium dataset. The performance of the adsorbent was also found satisfactory with field samples and can be considered a potential adsorbent for aqueous defluoridation.

Metal organic frameworks as polysulfide reaction modulators for lithium sulfur batteries: advances and perspectives.

Currently, lithium sulfur (Li-S) battery with high theoretical energy density has attracted great research interest. However, the diffusion and loss process of intermediate lithium polysulfide during charge-discharge hindered the application of the Li-S batteryin modern life. To overcome this issue, metal organic frameworks (MOFs) and their composites have been regarded as effective additions to restrain the LiPS diffusion process for Li-S battery. Benefiting from the unique structure with rich active sites to adsorb LiPS and accelerate the LiPS redox, the Li-S batteries with MOFs modified exhibit superior electrochemical performance. Considering the rapid development of MOFs in Li-S battery, this review summarizes the recent researches of MOFs and their composites as the sulfur host materials, functional interlayer, separator coating layer, and separator/solid electrolyte for Li-S batteries in detail. In addition, the promising design strategies of functional MOF materials are proposed to improve the electrochemical performance of Li-S battery.

Sustainable Gas Storage: CO2 Activation of Edge-Functionalized Graphitic Nanoplatelets.

Graphitic nanoplatelets (GnPs), edge-selectively carboxylated graphitic nanoplatelets (ECGnPs), are functionalized with a carboxylic acid at the edge increasing their surface area, and are highly dispersible in various solvents. However, there is a limit in that the basal plane remains intact because it is functionalized only in the part where the radical is generated at the edge. Here, we activate ECGnPs to have porous structures by flowing CO2 at 900 °C. Etching of the ECGnPs structure was performed through the Boudouard reaction, and the surface area increased from 579 m2 g-1 to a maximum of 2462 m2 g-1. In addition, the pore structure was investigated with various adsorption gases (CH4, Ar, CO2, H2, and N2) according to the reaction time. This study provides the overall green chemistry in that it utilizes CO2 from manufacturing to activation compared to the process of activating with conventional chemical treatment.

Enhanced adsorption of phenolic compounds using biomass-derived high surface area activated carbon: Isotherms, kinetics and thermodynamics.

The progress of industrial and agricultural pursuits, along with the release of inadequately treated effluents especially phenolic pollutant, has amplified the pollution load on environment. These organic compounds pose considerable challenges in both drinking water and wastewater systems, given their toxicity, demanding high oxygen and limited biodegradability. Thus, developing an eco-friendly, low-cost and highly efficient adsorbent to treat the organic pollutants has become an important task. The present investigation highlights development of a novel adsorbent (CFPAC) by activation of Cassia fistula pod shell for the purpose of removing phenol and 2,4-dichlorophnenol (2,4-DCP). The significant operational factors (dosage, pH, concentration, temperature, speed) were also investigated. The factors such as pH = 2 and T = 20°C were found to be significant at 1.6 g/L and 0.6 g/L dosage for phenol and 2,4-DCP respectively. Batch experiments were further conducted to study isotherms, kinetic and thermodynamics studies for the removal of phenol and 2,4-DCP. The activated carbon was characterised as mesoporous (specific surface area 1146 m2/g, pore volume = 0.8628 cc/g), amorphous and pHPZC = 6.4. At optimum conditions, the maximum sorption capacity for phenol and 2,4-DCP were 183.79 mg/g and 374.4 mg/g respectively. The adsorption isotherm was better conformed to Redlich Peterson isotherm (phenol) and Langmuir isotherm (2,4-DCP). The kinetic study obeyed pseudo-second-order type behaviour for both the pollutants with R2 > 0.999. The thermodynamic studies and the value of isosteric heat of adsorption for both the pollutants suggested that the adsorption reaction was dominated by physical adsorption (ΔHx < 80 kJ/mol). Further, the whole process was feasible, exothermic and spontaneous in nature. The overall studies suggested that the activated carbon synthesised from Cassia fistula pods can be a promising adsorbent for phenolic compounds.

Tackling antibiotic contaminations in wastewater with novel Modified-MOF nanostructures: A study of molecular simulations and DFT calculations.

The contamination of wastewater with antibiotics has emerged as a critical global challenge, with profound implications for environmental integrity and human well-being. Adsorption techniques have been meticulously investigated and developed to mitigate and alleviate their effects. In this study, we have investigated the adsorption behaviour of Erythromycin (ERY), Gentamicin (GEN), Levofloxacin (LEVO), and Metronidazole (MET) antibiotics as pharmaceutical contaminants (PHCs) on amide-functionalized (RC (=O)NH2)/MIL-53 (Al) (AMD/ML53A), using molecular simulations and density functional theory (DFT) calculations. Based on our Density Functional Theory (DFT) calculations, it becomes apparent that the adsorption tendencies of antibiotics are predominantly governed by the presence of AMD functional groups on the adsorbent surface. Specifically, hydrogen bonding (HB) and van der Waals (vdW) interactions between antibiotics and AMD groups serve as the primary mechanisms facilitating adsorption. Furthermore, we have observed that the adsorption behaviors of these antibiotics are influenced by their respective functional groups, molecular shapes, and sizes. Our molecular simulations delved into how the AMD/ML53A surfaces interact with antibiotics as PHCs. Moreover, various chemical quantum descriptors based on Frontier Molecular Orbitals (FMO) were explored to elucidate the extent of AMD/ML53A adsorption and to assess potential alterations in their electronic properties throughout the adsorption process. Monte Carlo (MC) calculations showed the following order for adsorption energy: ERY (-404.47 kcal/mol) > GEN (-230.99 kcal/mol) > LEVO (-229.66 kcal/mol) > MET (-184.14 kcal/mol). Molecular dynamics (MD) simulations revealed parallel orientation for the ERY molecule's adsorption on AMD/ML53A with 80% rejection rate. In conclusion, our study highlighted the importance of modeling in developing practical solutions for removing antibiotics as PHCs from wastewater. The insights gained from our calculations can facilitate the design of more effective adsorption materials, ultimately leading to a more hygienic and sustainable ecosystem.

Scaling Supercapacitive Swing Adsorption of CO2 Using Bipolar Electrode Stacks.

Supercapacitive swing adsorption (SSA) modules with bipolar stacks having 2, 4, 8, and 12 electrode pairs made from BPL 4 × 6 activated carbon are constructed and tested for carbon dioxide capture applications. Tests are performed with simulated flue gas (15%CO2 /85%N2) at 2, 4, 8, and 12 V, respectively. Reversible adsorption with sorption capacities (≈58 mmol kg-1) and adsorption rates (≈38 µmol kg-1 s-1) are measured for all stacks. The productivity scales with the number of cells in the module, and increases from 70 to 390 mmol h-1 m-2. The energy efficiency and energy consumption improve with increasing number of bipolar electrodes from 67% to 84%, and 142 to 60 kJ mol-1, respectively. Overall, the results show that SSA modules with bipolar electrodes can be scaled without reducing the adsorptive performance, and with improvement of energetic performance.

Fast and efficient As(III) removal from water by bifunctional nZVI@NBC.

As a notable toxic substance, metalloid arsenic (As) widely exists in water body and drinking As-contaminated water for an extended period of time can result in serious health concerns. Here, the performance of nanoscale zero-valent iron (nZVI) modified N-doped biochar (NBC) composites (nZVI@NBC) activated peroxydisulfate (PDS) for As(III) removal was investigated. The removal efficiencies of As(III) with initial concentration ranging from 50 to 1000 µg/L were above 99% (the residual total arsenic below 10 µg/L, satisfying the contaminant limit for arsenic in drinking water) within 10 min by nZVI@NBC (0.2 g/L)/PDS (100 µM). As(III) removal efficiency influenced by reaction time, PDS dosage, initial concentration, pH, co-existing ions, and natural organic matter in nZVI@NBC/PDS system were investigated. The nZVI@NBC composite is magnetic and could be conveniently collected from aqueous solutions. In practical applications, nZVI@NBC/PDS has more than 99% As(III) removal efficiency in various water bodies (such as deionized water, piped water, river water, and lake water) under optimized operation parameters. Radical quenching and EPR analysis revealed that SO4·- and ·OH play important roles in nZVI@NBC/PDS system, and the possible reaction mechanism was further proposed. These results suggest that nZVI@NBC activated peroxydisulfate may be an efficient and fast approach for the removal of water contaminated with As(III).

Separation of Mono-/Divalent Ions via Controlled Dynamic Adsorption/Desorption at Polythiophene Coated Carbon Surface with Flow-Electrode Capacitive Deionization.

Capacitive deionization for selective separation of ions is rarely reported since it relies on the electrostatic attraction of oppositely charged ions with no capability to distinguish ions of different valent states. Using molecular dynamic simulation, a screening process identified a hybrid material known as AC/PTh, which consists of activated carbon with a thin layer of polythiophene (PTh) coating. By utilizing AC/PTh as electrode material implementing the short-circuit cycle (SCC) mode in flow-electrode capacitive deionization (FCDI), selective separation of mono-/divalent ions can be realized via precise control of dynamic adsorption and desorption of mono-/divalent ions at a particular surface. Specifically, AC/PTh shows strong interaction with divalent ions but weak interaction with monovalent ions, the distribution of divalent ions can be enriched in the electric double layer after a couple of adsorption-desorption cycles. At Cu2+/Na+ molar ratio of 1:40, selectivity toward divalent ions can reach up to 110.3 in FCDI SCC mode at 1.0 V. This work presents a promising strategy for separating ions of different valence states in a continuously operated FCDI device.

Adsorption of sulfamethoxazole and lincomycin from single and binary aqueous systems using acid-modified biochar from activated sludge biomass.

The extensive use of pharmaceuticals has raised growing concerns regarding their presence in surface waters. High concentrations of sulfamethoxazole (SMX) and lincomycin (LIN), as commonly prescribed antibiotics, persist in various wastewaters and surface waters, posing risks to public health and the environment. Biochar derived from accessible biowaste, like activated sludge biomass, offers a sustainable and eco-friendly solution to mitigate antibiotic release into water systems. This study investigates the effectiveness of H3PO4-modified activated sludge-based biochar (PBC) synthesized through microwave (MW) heating for the adsorption of SMX and LIN antibiotics. The synthesis parameters of PBC were optimized using a central composite design considering MW power, time, and H3PO4 concentration. Characterization results validate the efficacy of the synthesis process creating a specific surface area of 365 m2/g, and well-developed porosity with abundant oxygen-containing functional groups. Batch and dynamic adsorption experiments were piloted to assess the adsorption performance of PBC in single and binary antibiotic systems. Results show that PBC exhibits a higher affinity for SMX rather than LIN, with maximum adsorption capacities of 45.6 mg/g and 26.6 mg/g, respectively. Based on kinetic studies chemisorption is suggested as the primary mechanism for SMX and LIN removal. Equilibrium studies show a strong agreement with the Redlich-Peterson isotherm, suggesting a composite adsorption mechanism with a greater probability of multilayer adsorption for both antibiotics. Hydrogen bonding and π-π electron sharing are suggested as the prevailing adsorption mechanisms of SMX and LIN on the modified biochar. Furthermore, a dynamic adsorption system was replicated using a fixed bed column setup, demonstrating effective removal of SMX and LIN from pure water and real wastewater samples using PBC-loaded hydrogel beads (PBC-B). These findings serve as crucial support for upcoming studies concerning the realistic application of sludge-based biochar in the removal of antibiotics from water systems.

Valorization of pyrolysis oils recycled from waste car tires as potential collector in coal flotation: Production, characterization, and collecting mechanism.

The present research study investigates the performance of pyrolysis oils recycled from waste tires as a collector in coal flotation. Three different types of pyrolysis oils (namely, POT1, POT2, and POT3) were produced through a two-step pressure pyrolysis method followed by an oil rolling process. The characteristics of POTs were adjusted using various oil-modifying additives such as mineral salts and organic solvents. The chemical structure of POTs was explored by employing necessary instrumental analysis techniques, including microwave-assisted acid digestion (MAD), inductively coupled plasma atomic emission spectroscopy (ICP-AES), Fourier-transform infrared spectroscopy (FT-IR), and gas chromatography-mass spectrometry (GC-MS). The collecting performance of POTs in coal flotation was evaluated using an experimental design based on Response Surface Methodology (RSM), considering the ash content and yield of the final concentrate. The effect of the type and dosage of POTs was evaluated in conjunction with other important operating variables, including the dosage of frother, dosage of depressant, and the type of coal. Results of POTs characterization revealed that the pyrolysis oils were a complex composition of light and heavy hydrocarbon molecules, including naphthalene, biphenyl, acenaphthylene, fluorene, and pyrene. Statistical analysis of experimental results showed that among different POTs, POT1 exhibited remarkable superiority, achieving not only a 15% higher coal recovery but also a 12% lower ash content. The outstanding performance of POT1 was attributed to its unique composition, which includes a concentrated presence of carbon chains within the optimal range for efficient flotation. Additionally, the FT-IR spectra of POT1 reveal specific functional groups, including aromatic and aliphatic compounds, greatly enhancing its interaction with coal surfaces, as confirmed by contact angle measurement. This research provides valuable insights into the specific carbon chains and functional groups that contribute to the effectiveness of POT as a collector, facilitating the optimization of coal flotation processes and underscoring the environmental advantages of employing pyrolysis oils as sustainable alternatives in the mining industry.

Enhanced degradation and removal of ciprofloxacin and ofloxacin through advanced oxidation and adsorption processes using environmentally friendly modified carbon nanotubes.

This study explores the utilization of adsorption and advanced oxidation processes for the degradation of ofloxacin (OFL) and ciprofloxacin (CIP) using a green functionalized carbon nanotube (MWCNT-OH/COOH-E) as adsorbent and catalyst material. The stability and catalytic activity of the solid material were proved by FT-IR and TG/DTG, which also helped to elucidate the reaction mechanisms. In adsorption kinetic studies, both antibiotics showed similar behavior, with an equilibrium at 30 min and 60% removal. The adsorption kinetic data of both antibiotics were well described by the pseudo-first-order (PFO) model. Different advanced oxidation processes (AOPs) were used, and the photolytic degradation was not satisfactory, whereas heterogeneous photocatalysis showed high degradation (⁓ 70%), both processes with 30 min of reaction. Nevertheless, ozonation and catalytic ozonation have resulted in the highest efficiencies, 90%, and 70%, respectively, after 30-min reaction. For AOP data modeling, the first-order model better described CIP and OFL in photocatalytic and ozonation process. Intermediates were detected by MS-MS analysis, such as P313, P330, and P277 for ciprofloxacin and P391 and P332 for ofloxacin. The toxicity test demonstrated that a lower acute toxicity was observed for the photocatalysis method samples, with only 3.1 and 1.5 TU for CIP and OFL, respectively, thus being a promising method for its degradation, due to its lower risk of inducing the proliferation of bacterial resistance in an aquatic environment. Ultimately, the analysis of MWCNT reusability showed good performance for 2 cycles and regeneration of MWCNT with ozone confirmed its effectiveness up to 3 cycles.

Cellulose acetate nanofiber modified with polydopamine polymerized MOFs for efficient removal of noxious organic dyes.

The need to effectively remove toxic organic dyes from aquatic systems has become an increasingly critical issue in the recent years. In pursuit of this objective, polydopamine (PDA)-binary ZIF-8/UiO-66 (MOFs) was synthesized and incorporated into cellulose acetate (CA), producing ZIF-8/UiO-66/PDA@CA composite nanofibers under meticulously optimized conditions. The potential of fabricated nanofibers to remove cationic methylene blue (MB) dye was investigated. Various analysis tools including FTIR, XRD, SEM, zeta potential, BET, tensile strength testing, and XPS were employed. Results revealed a substantial leap in tensile strength, with ZIF-8/UiO-66/PDA@CA registering an impressive 2.8 MPa, as a marked improvement over the neat CA nanofibers (1.1 MPa). ZIF-8/UiO-66/PDA@CA nanofibers exhibit an outstanding adsorption capacity of 82 mg/g, notably outperforming the 22.4 mg/g capacity of neat CA nanofibers. In binary dye systems, these nanofibers exhibit a striking maximum adsorption capacity of 108 mg/g, establishing their eminence in addressing the complexities of wastewater treatment. Furthermore, the adsorption data fitted to the Langmuir isotherm, and the pseudo-second-order kinetic model. The fabricated nanofiber demonstrates good reproducibility and durability, consistently upholding its performance over five cycles. This suite of remarkable attributes collectively underscores its potential as a robust, durable, and highly promising solution for the effective and efficient removal of pernicious MB dye, in the context of both water quality improvement and environmental preservation.