Synergistic Effect Of Adsorption Research Articles

The adsorption behavior and mechanism of Cu(Ⅱ), Fe(Ⅱ) and Co(Ⅱ) on straw biochar and their Fenton-like performance for ciprofloxacin decontamination.

In this study, the adsorption of aqueous Cu(Ⅱ), Fe(Ⅱ), and Co(Ⅱ) on biochars at diverse synthesized temperatures was evaluated. The optimal sample BC-800 achieved superior adsorption performance of Cu(Ⅱ), Fe(Ⅱ), and Co(Ⅱ) at 10-50mgL-1 initial concentration. Due to the larger surface area (349.6m2/g), total pore volume (0.24cm3/g), average pore diameter (6.4nm), higher degree of graphitization (IG/ID=1.00) and stable aromatic carbon structure, BC-800 achieved excellent adsorption of Cu(Ⅱ), Fe(Ⅱ), and Co(Ⅱ) through multilayer chemical adsorption, corresponding to the pseudo-2nd-order and Freundlich model (Qm Cu(Ⅱ)=433.4mgg-1, Qm Fe(Ⅱ)=472.0mgg-1 and Qm Co(Ⅱ)=301.0mgg-1). After then, the adsorbed biochars with Cu(Ⅱ), Fe(Ⅱ), and Co(Ⅱ) were directly used as heterogeneous catalysts in Fenton-like reaction for ciprofloxacin (CIP) degradation. Compared with Co-BC-800/peroxymonosulfate (PMS) system, Co-BC-800/H2O2 system exhibited the 56.6% decontamination of CIP with lower ions leaching (0.53mg/L) within 70min. The 97.9% of CIP was finally removed by Co-BC-800/H2O2 under optimized conditions: initial pH=6.94, catalyst dosage=1.0gL-1, H2O2 concentration=0.44gL-1. Furthermore, Co-BC-800 exhibited superior acid-base adaptability (2.94-10.94) and anti-anion interference ability. The removal of CIP was achieved by the synergistic effect of adsorption and oxidative degradation. This study proposes some insights into the behavior and mechanism of metal ions adsorption on biochar and hazardous waste treatment.

Adsorption-catalytic synergistic Fenton degradation of potassium butyl xanthate in flotation tailing wastewater by renewable iron-loaded sludge: Performance, kinetics and mechanism

The renewable iron-loaded residual sludge heterogeneous catalyst (RLS-Fe) was prepared by impregnation-pyrolysis method and applied to the heterogeneous Fenton for the degradation of potassium butyl xanthate (BX-K) in flotation tailing wastewater. The rich pore structure and uniformly distributed iron oxides endowed the catalyst with excellent adsorption and catalytic capabilities. RLS-Fe exhibited maximum adsorption capacity of 86.47 mg/g, with surface concentration (Cs) of 2.88 mg/cm2 and surface coverage (θ) exceeding 80 %. The interaction of monolayer-adsorbed BX-K with catalytically generated ·OH facilitated the Fenton reaction and enhanced the adsorption process, making the degradation and mineralization of BX-K more efficient, with the removal rate of 99.82 % in 80 min. Through the synergistic effects of adsorption and catalytic processes, H2O2 was efficiently decomposed and effectively utilized. The ·OH generated in the initial stage rapidly degraded the adsorbed BX-K and released the adsorption sites, while the ·O2– produced subsequently targeted the catalytic sites and restored their activity. The Langmuir-Hinshelwood (L-H) kinetic model confirmed that the mutual promotion of adsorption and catalysis elevated the apparent reaction rate constant and accelerated the mineralization of BX-K. Additionally, density functional theory (DFT), Fukui indices and Gibbs free energy calculations were employed to analyze the intermediates and degradation pathways of BX-K. The −C=S– bond was identified as the primary target for ·OH attack. The RLS-Fe catalyst prepared in this study presented excellent stability and renewability, offering new insights for the streamlined preparation of renewable catalysts and efficient treatment of tailings wastewater.

A highly efficient bifunctional Z-scheme photocatalyst with spatially-separated and synergistically-enhanced adsorption and photodegradation

Adsorption-enhanced photodegradation and its unique kinetics are studied in a bifunctional Z-scheme photocatalyst. MoS2 nanoflakes are selectively deposited on the edges of TiO2 nanosheets to form an edge-connected MoS2/Au/TiO2 Z-scheme heterostructured photocatalyst, with rapid pollutant adsorption on MoS2 surfaces and subsequent degradation on TiO2 surfaces. The spatial separation of two components promotes the formation of Z-scheme charge transfer and maintains the effective bifunctions. As a result, the optimal system (10 %MoS2/Au/TiO2) could remove up to 90 % of pollutant within 30 mins and subsequently eliminates the residue to a level below ppm. Detailed study on the synergistic effects of adsorption and photodegradation indicates that the system exhibits an adsorption-enhanced photodegradation due to the pre-concentration effect by MoS2 and a surface-diffusion mechanism of pollutant molecules migrating from MoS2 to TiO2. This work provides a novel strategy in designing the bifunctional photocatalyst for effective water treatment.

Spontaneous built-in electric field in W-W2C@C heterostructure: Accelerating Sn2- directed migration in Li-S batteries

The commercialization of Li-S batteries is severely hindered by shuttle effect and sluggish redox reaction kinetics of LiPSs. Heterostructure can resolve the above shortcomings through the synergistic effect of adsorption and catalysis. However, long-chain LiPSs dissolving in electrolyte tend to cluster, resulting in low sulfur utilization and preventing kinetic conversion Thus, it is necessary to regulate the diffusion of Sn2− to achieve the directional diffusion from adsorbent to catalyst. Nevertheless, the design principle has not yet been clarified. W-W2C@C heterostructure with W of strong adsorption ability and high work function and W2C of excellent catalytic activity and low work function is designed by theoretical screening. Due to work function difference, this heterostructure controls the direction of the interface built-in electric field (BIEF), realizing the directional migration process of Sn2− from adsorptive W to catalytic W2C, thereby achieving a continuous “trapping-directional migration-conversion” reaction mechanism. The batteries have an excellent Li+ diffusion rate, high initial discharge specific capacity (1400.6 mAh/g at 0.2C), excellent rate capability (853.2 mAh/g at 2C), high reversible capacity (977.9 mAh/g after 150 cycles at 0.2C) and an extremely low capacity decay rate of 0.09 % per cycle after 300 cycles at 1C.

Self-Assembly of Nanovesicles for Enhanced Adsorption and Efficient Photodegradation of 2,4,6-Trichlorophenol.

The compound 2,4,6-trichlorophenol poses significant risks to both the aquatic environment and human health. Its inherent persistence and stability present challenges in achieving complete purification, thus warranting its inclusion as a priority pollutant. The present study reports the development of an amphiphilic small-molecule compound that self-assembles into nanovesicles exhibiting remarkable adsorption and photodegradation capabilities. Through the synergistic effects of hydrogen bonding, van der Waals forces, π-π interactions, and electrostatic interactions, these vesicles efficiently adsorb 2,4,6-trichlorophenol from aqueous solutions within 1 min while demonstrating exceptional environmental stability and broad applicability. Upon self-assembly into vesicles, not only are more adsorption sites exposed, but charge separation and migration within the vesicles are also facilitated. Through the synergistic effects of adsorption and photodegradation, complete removal of 2,4,6-trichlorophenol in aqueous solution can be achieved within 8 h while exhibiting excellent recycling capability. This approach offers a viable strategy for designing and synthesizing pure organic photodegradable materials.

Effect of solvothermal reaction time on adsorption and photocatalytic activity of spinel ZnFe2O4 nanoparticles

The present investigation explored the impact of solvothermal reaction time on the adsorption properties of synthesized spinel ZnFe2O4 Nanoparticles (ZF NPs) and their photocatalytic activity for the degradation of congo red (CR) dye. The structure, morphology and chemical composition is identified for the synthesized ZF NPs. The reaction times for the solvothermal synthesis of ZF NPs were investigated at time intervals of 6 hrs and 18 hrs which are denoted as ZF-6 h and ZF-18 h respectively. The XRD confirms the formation of spinel-type ZF-6 h and ZF-18 h with crystallite size of 5.50 nm and 8.36 nm for ZF-6 h and ZF-18 h respectively. The FESEM image of ZF-6 h exhibits microspheres, whereas in ZF-18 h NPs, the microspheres undergoes deformation. TEM analysis of ZF-6 h revealed that the microspheres were consists of 8–10 nm size ZF-NPs. Raman spectroscopy and XPS studies indicates, the reaction time influence the occupancy with 64 % and 32 % of inversion of Zn2+ cations from tetrahedral to octahedral sites in ZF-6 h and ZF-18 h, respectively. The surface area of mesoporous ZF-6 h and ZF-18 h are 138.29 m2/g and 128.41 m2/g respectively as confirmed using BET and BJH techniques. The CR dye adsorption capacity of 123.73 mg/g for ZF-6 h is higher compared to ZF-18 h (99.93 mg/g). The maximum dye removal efficiency evaluated for ZF-6 h NPs and ZF-18 h NPs was 87.33 % and 73.09 % respectively upon exposure of natural sunlight. The recyclability study identifies that ZF-6 h NPs remain stable for three degradation cycles. These results indicate that reaction time in solvothermal synthesis is sensitive to the morphology and physicochemical properties of ZF NPs. The enhanced performance of such ZF NPs is attributed to the synergistic effect of adsorption followed by photocatalytic (photo-Fenton) degradation of dyes.

Insight into photocatalytic chlortetracycline degradation by WO3/AgI S-scheme heterojunction: DFT calculation, degradation pathway and electron transfer mechanism

The construction of S-scheme heterojunction with excellent redox ability holds promising prospects for photocatalytic environment remediation. However, the rationally design of the heterojunction interface to achieve efficient charge transfer still faces challenges. In this study, we fabricated a tight-contacted S-scheme heterojunction by in situ anchoring AgI nanoparticles onto WO3 nanoplates. The significant difference in Fermi energy levels between WO3 and AgI results in the formation of a space charge region around the interface and bending of the energy band, facilitating directional migration and spatial separation of charge carriers. This contributes to enhanced generation of superoxide radicals (•O2−) and holes (h+) active species, leading to a significant increase in chlortetracycline (CTC) degradation rate. The apparent rate constant for CTC removal using the WO3/AgI (WA-2) is approximately 15 times higher than that observed for pure WO3. Furthermore, WA-2 exhibits universal degradation effects on tetracycline (TC) and oxytetracycline (OTC). Molecular dynamics (MD) simulation reveals the synergistic adsorption effect of WO3 and AgI on CTC and reactive oxygen species molecules. Based on Fukui function calculation of CTC molecules and degradation intermediates, liquid chromatography-mass spectrometry (LC-MS) analysis, photocatalytic degradation pathway over WO3/AgI was determined to be sequential demethylation followed by dechlorination and decarbonylation. These findings provide valuable insights into high-performance S-scheme heterojunctions interface design and elucidation of pollutant degradation mechanism.

Application of porous silica supported GdFeO3 as adsorbent and photo‐Fenton catalyst for removal of rose bengal

AbstractThe synergistic effect of adsorption and photo‐Fenton process of rose bengal (RB) onto the GdFeO3‐impregnated porous silica (GFO/PS) was investigated by varying GFO loading over mesoporous silica, RB concentration, adsorbent dosage, initial pH of solution, contact time of adsorption and photo‐Fenton efficiency. The adsorption capability of RB onto GFO/PS was found to reduce by increasing the adsorbent dosage and solution pH. Meanwhile, GFO/PS photocatalyst exhibited a good performance under visible light illumination. The improvement in photo‐Fenton performance of GFO/PS could be ascribed to its large specific surface area and small band gap energy. The GFO/PS also showed good adsorption capability and high photo‐Fenton catalytic activity, suggesting it as a promising material for use to remove RB from wastewater.

Synergistic effect of adsorption and electrocatalysis of ZnO@MnO2 PCNFs for high-performance lithium-sulfur batteries

Catalytic conversion is a new strategy to mitigate the shuttle effects of lithium-sulfur batteries, but the catalyst must play an effective role in both oxidation and reduction processes. In this paper, a lotus root-like ZnO@MnO2 PCNFs with a built-in electric field are proposed as cathodes for lithium-sulfur batteries. Due to the synergistic effect of both components, ZnO@MnO2 PCNFs demonstrated outstanding bidirectional catalytic performance, with ZnO primarily enhancing catalysis and MnO2 regulating adsorption. The ZnO@MnO2 PCNFs exhibit higher initial capacity (1582 mAh g−1 at 0.1 C), and longer cycle life (2000 cycles with 0.023 % decay per period at 2 C). Even under high S loading of 8.32 mg cm−2 and a low electrolyte to sulfur ratio is about 4.8 μL mg−1, the cell with ZnO@MnO2 PCNFs shows a discharge capacity of 688.6 mAh g−1 at 0.2 C, and maintained at 420.9 mAh g−1 after 100 cycles. This approach has shown promise in improving the efficiency and cycling stability of Li-S batteries, making them more viable for practical applications.

Enhanced photocatalytic performance of 0.1Bi-MIL-101-NH2 after phosphorus adsorption: Synergistic effect of adsorption and photocatalysis

Achieving efficient phosphorus recovery and reuse from wastewater presents formidable challenges. In this study, a synergistic adsorption photocatalysis process was successfully constructed. 0.1Bi-MIL-101-NH2 showed the maximum phosphorus adsorption performance of 112 mg/g. After phosphorus adsorption, photoelectrochemical measurements confirmed that the photoelectric properties of the 0.1Bi-MIL-101-NH2-P sample was improved, and the degradation efficiency of SMX was increased by 20 % within 120 min. Meanwhile, the mineralization rate reached 91 %. The incorporation of Bi significantly enhanced the adsorption energy of the 0.1Bi-MIL-101-NH2 sample. Notably, the presence of phosphorus on the surface of 0.1Bi-MIL-101-NH2-P enhanced the adsorption of water molecules by the material, thereby augmenting the generation of •OH. •O2- and •OH played dominant roles in the photodegradation of SMX. Finally, the degradation pathways of intermediates were further studied by Density functional theory (DFT) calculations and LC-MS analysis. This study provides a new avenue for phosphorus recovery and organic pollutant degradation.

Pd0–Ov–Ce3+ Interfacial Sites with Charge Redistribution for Enhanced Hydrogenation of Methyl Oleate to Methyl Stearate

Improving the efficiency of metal/reducible metal oxide interfacial sites for hydrogenation reactions of unsaturated groups (e.g., C=C and C=O) is a promising yet challenging endeavor. In our study, we developed a Pd/CeO2 catalyst by enhancing the oxygen vacancy (OV) concentration in CeO2 through high-temperature treatment. This process led to the formation of an interface structure ideal for supporting the hydrogenation of methyl oleate to methyl stearate. Specifically, metal Pd0 atoms bonded to the OV in defective CeO2 formed Pd0–OV–Ce3+ interfacial sites, enabling strong electron transfer from CeO2 to Pd. The interfacial sites exhibit a synergistic adsorption effect on the reaction substrate. Pd0 sites promote the adsorption and activation of C=C bonds, while OV preferably adsorbs C=O bonds, mitigating competition with C=C bonds for Pd0 adsorption sites. This synergy ensures rapid C=C bond activation and accelerates the attack of active H* species on the semi-hydrogenated intermediate. As a result, our Pd/CeO2-500 catalyst, enriched with Pd0–OV–Ce3+ interfacial sites, demonstrated excellent hydrogenation activity at just 30 °C. The catalyst achieved a Cis–C18:1 conversion rate of 99.8% and a methyl stearate formation rate of 5.7 mol/(h·gmetal). This work revealed the interfacial sites for enhanced hydrogenation reactions and provided ideas for designing highly active hydrogenation catalysts.

Sodium humate as green corrosion inhibition for enhanced corrosion resistance of EH40 ship plate steel

A new green corrosion inhibitor was extracted and prepared from available and inexpensive natural humic plant humus for the corrosion inhibition of EH40 steel in a 15 % HCl medium. The corrosion inhibition properties of SH were evaluated using weight loss, cyclic voltammetry, potentiodynamic polarization and electrochemical impedance spectroscopy. The morphology of EH40 steel was characterized using scanning electron microscopy, atomic force spectroscopy and x-ray photoelectron spectroscopy. It was found that, the optimum concentration of sodium humate was 1.0 gL−1 with an inhibition efficiency of above 95 %. The corresponding corrosion inhibition mechanism was proposed, in which the corrosion inhibitor formed a film on the surface of EH40 steel as a result of the synergistic adsorption effect of chemistry and physics, improving its corrosion retention in the strong acid medium.

Synergistic effect of adsorption and photolysis on methylene blue removal by magnetic biochar derived from lignocellulosic biomass

In this study, magnetic biochar was synthesized by doping Fe3O4 onto the biochar surface followed by analysis of its properties. The efficiency of methylene blue (MB) removal through the combined processes of adsorption and photolysis was assessed. The presence of Fe3O4 on the biochar surface was confirmed using Raman spectroscopy and X-ray photoelectron spectroscopy. The magnetic biochar, after MB adsorption, showed a magnetism of 39.50 emu/g leading to a 97.07 % recovery rate. The specific surface area of biochar was higher (380.68 m2/g) than that of magnetic biochar (234.46 m2/g), and the maximum adsorption capacity of MB was higher in the biochar (0.03 mg/g) than that in magnetic biochar (0.02 mg/g) under the optimal conditions for MB adsorption. The MB adsorption experiments using biochar or magnetic biochar were optimally conducted under 10–20 mg/L MB concentration, 1 g biochar dosage, pH 12, 200 rpm rotation speed, 25 °C temperature, and 30 min duration. Under dark conditions, biochar had a higher MB removal rate, at 83.91 %, compared to magnetic biochar, at 78.30 %. Under visible light (λ > 425 nm), magnetic biochar effectively removed MB within 10 min, highlighting the synergistic effect of adsorption and photolysis. MB is physically and chemically adsorbed by the monolayer on the surface of EB and EMB according to adsorption behavior.

Removal of hypertoxic Cr(VI) from water by polyaniline-coated ZIF-67-derived nitrogen-doped magnetic carbon.

Heavy metals are highly toxic and nonbiodegradable, posing a serious threat to the water environment and human beings. Therefore, it is crucial to develop a highly efficient adsorbent that is easy to recover and separate for the removal of heavy metals. In this paper, nitrogen-doped magnetic carbon (NC-67) was prepared by carbonization and hydrochloric acid treatment using cobalt-containing MOF (ZIF-67) as precursor. Then, polyaniline (PANI) was grown directly on NC-67 with high specific surface area by in situ polymerization to prepare polyaniline-coated nitrogen-doped magnetic carbon (NC-67@PANI), which was characterized by XRD, SEM, TEM and VSM, etc. and used for the removal of Cr(VI)from wastewater. The experimental results showed that the adsorption process of Cr(VI) by NC-67@PANI was spontaneous and endothermic, which conformed to the pseudo-second-order model and Freundlich adsorption isotherm model. Due to the synergistic effect of adsorption and reduction, the experimental adsorption capacity of NC-67@PANI for Cr(VI) was 410.2 mg/g. NC-67@PANI maintained a removal efficiency of 65.8% for Cr(VI) after five cycles. In addition, NC-67@PANI had good magnetism and was easy to separate under external magnetic field. The excellent adsorption capacity and easy separation characteristics of NC-67@PANI indicate that it is a promising adsorbent for Cr(VI) removal from wastewater.

Construction of novel biochar/g-C3N4/BiOBr heterojunction with S-scheme mechanism for efficient photocatalytic degradation of tetracycline

In this work, a novel biochar/g-C3N4/BiOBr (BCN/BiOBr) S-scheme heterojunction was synthesized for the removal of tetracycline (TC) under visible light. The 0.75-BCN/BiOBr heterojunction exhibited a significantly higher degradation efficiency of TC in wastewater under visible light excitation, achieving about 86.5 % degradation in 72 minutes, which is 2.5 times higher than that of pure g-C3N4. Furthermore, the influence of factors such as pH, dosage of tetracycline and photocatalyst on TC degradation were investigated. Photochemical characterization experiments revealed that the enhanced degradation performance of the BCN/BiOBr heterojunction stemmed from the synergistic effects of adsorption and photocatalysis, providing more active sites to promote the photocatalytic reaction, and accelerating accelerate charge separation and light absorption ability. Meanwhile, the results from the active species indicated that h+, ·OH, and ·O2- play major roles in the degradation process. Additionally, the mechanism research revealed that the photogenerated carriers followed an S-scheme step transfer pathway at the interface of BiOBr and g-C3N4, and the two possible pathways for TC degradation. This provides guidance for improving wastewater treatment using biochar-modified high-efficiency S-scheme photocatalysts.

Visible light photocatalytic degradation of oxytetracycline hydrochloride using chitosan-loaded Z-scheme heterostructured material BiOCOOH/O-gC3N4

In this work, a Z-scheme heterostructured BiOCOOH/O-gC3N4 material was synthesized and immobilized on chitosan (CTS) to obtain the BiOCOOH/O-gC3N4/CTS photocatalytic material for photocatalytic degradation of oxytetracycline hydrochloride (CTC).Our findings indicate that the composite material BiOCOOH/O-gC3N4, as well as the BiOCOOH/O-gC3N4/CTS composite membrane, displayed a significantly higher efficiency in photocatalytic degradation of CTC compared to BiOCOOH alone, owing to the synergistic effect of adsorption and photocatalysis. Following four cycles of use, the composite material retained around 96 % of its initial photocatalytic degradation activity. The addition of CTS in the photocatalytic material resolved issues such as aggregation and difficult recovery commonly encountered with powder materials, thereby facilitating effective collision between the photocatalytic active sites and CTC. Experimental and theoretical calculations provided confirmation that the combination of BiOCOOH and O-gC3N4 effectively enhanced the light absorption capacity and photocatalytic performance. Furthermore, we investigated the influence of environmental factors such as pH value and anions on the photocatalytic degradation experiment, which offers valuable insights for the application of composite catalysts in wastewater treatment.

Synergistic rapid removal of U(VI) from radioactive wastewater by photoexcitation-driven Z-scheme heterojunction hydrogel

The development of inexpensive and efficient semiconductor catalysts for uranium removal from wastewater via photoreduction remains challenging. Herein, we successfully synthesized Z-scheme heterojunction LaOCl-ZnO-1.5 photocatalyst by ultrasound-assisted in-situ deposition technology followed by immobilization in sodium alginate (SLZ-1.5) by an embedding strategy for the reductive removal of U(VI) from uranium-containing wastewater. The construction of a heterojunction achieves synergistic effects, improving optical response range and photocatalytic efficiency, reducing the loss of photocatalyst through immobilization in the gel structure, and simultaneously solving the difficulty of recycling powder catalysts. SLZ-1.5 demonstrated superior photocatalytic properties for the reduction of U(VI) and rapid reaction kinetics (120 min, 96.1 %) under visible-light irradiation by a xenon lamp. Through the synergistic effect of adsorption and photocatalysis, its optimal removal capacity for U(VI) reached 520.8 mg/g. SLZ-1.5 exhibited great recyclability and excellent selectivity (1.22 × 104 mL/g). In addition, the outstanding performance (98.6 %) of SLZ-1.5 in a dynamic adsorption column under visible-light irradiation validated its potential for practical applications. The photoreduction mechanism indicated that the excellent photocatalytic performance of LaOCl-ZnO-1.5 was enabled by its great light absorption capacity and appropriate bandgap. SLZ-1.5 heterojunction hydrogel is a successful example of a promising adsorption-reduction coupling material that can be applied for the purification and treatment of uranium-containing wastewater.

Boosted adsorption and oxidation performances in peroxymonosulfate (PMS)-based heterogeneous fenton-like reactions via P, N co-doping strategy

The heterogeneous Fenton-like reactions (HTFR) have attracted considerable interest for their efficacy in degrading pollutants. However, the development of effective strategies for enhancing performance in HTFR remains a subject of ongoing research. Herein, a synergistic adsorption and oxidation-dominated process was developed to overcome the bottlenecks of peroxymonosulfate (PMS)-based HTFR in terms of mass transfer and catalyst reactivity. Heteroatom (P, N) co-doping for manganese (Mn) was employed to fabricate an efficient catalyst, Mn@5-NPC-800, which exhibited exceptional abilities of adsorption and PMS activation. The enhanced performance of HTFR was attributed to the increased specific surface area (SSA) and enhanced yields of graphitic-N/MnIII of the catalyst, which facilitated reactant enrichment and electron transfer in the delocalized conjugated area, respectively. The PMS-based HTFR induced by Mn@5-NPC-800 for pollutant removal was characterized by a synergistic adsorption and reactive oxygen species (ROS)-dominated oxidation process. DFT calculations revealed that the N, P co-doped carbon matrix (NPC) acted as a conductive bridge, significantly improving electron transfer between MnP and PMS molecule, which was identified as a key factor in governing the catalytic performance. The investigation presents a suggestive example of employing a doping strategy to create a synergistic effect of adsorption and oxidation, thereby strengthening the performance of Fenton-like reactions.

Visible-light-driven calcium alginate hydrogel encapsulating BiOBr0.75I0.25 for efficient removal of oxytetracycline from wastewater

Oxytetracycline (OTC), a widely used antibiotic, poses significant environmental risks due to its persistence in ecosystems. This study introduces a visible-light-driven photocatalytic hydrogel system for effectively removing OTC from wastewater. The system employs calcium alginate (CA) hydrogel beads encapsulating a BiOBr0.75I0.25 solid solution, which utilizes the synergistic effects of adsorption and visible-light-driven photocatalysis. The BiOBr0.75I0.25 solid solution photocatalyst was synthesized via a solvothermal method, while CA hydrogel beads encapsulating BiOBr0.75I0.25 were prepared through ionic gelation of sodium alginate with calcium chloride. The novel hydrogel, CA-BiOBr0.75I0.25, demonstrated rapid adsorption, capturing over 50 % of OTC within 30 min and achieving a 90.92 % degradation rate within 60 min under visible light. This performance is associated with the unique petal-like structure of BiOBr0.75I0.25 and the high surface area of the hydrogel, facilitating efficient charge separation and radical generation critical for photocatalytic activity. Additionally, the system showed excellent stability and reusability, maintaining an 83 % removal efficiency after five cycles. These findings highlight the potential of this novel hydrogel as a sustainable solution for advanced wastewater treatment technologies.

Effects of TiO2 Nanoparticles Synthesized via Microwave Assistance on Adsorption and Photocatalytic Degradation of Ciprofloxacin.

In this study, the optimal microwave-assisted sol-gel synthesis parameters for achieving TiO2 nanoparticles with the highest specific surface area and photocatalytic activity were determined. Titanium isopropoxide was used as a precursor to prepare the sol (colloidal solution) of TiO2. Isopropanol was used as a solvent; acetylacetone was used as a complexation moderator; and nitric acid was used as a catalyst. Four samples of titanium dioxide were synthesized from the prepared colloidal solution in a microwave reactor at a temperature of 150 °C for 30 min and at a temperature of 200 °C for 10, 20, and 30 min. The phase composition of the TiO2 samples was determined by X-ray diffraction analysis (XRD) and Fourier-transform infrared spectroscopy (FTIR). Nitrogen adsorption/desorption isotherms were used to determine the specific surface area and pore size distributions using the Brunauer-Emmett-Teller (BET) method. The band-gap energy values of the TiO2 samples were determined by diffuse reflectance spectroscopy (DRS). The distribution of Ti and O in the TiO2 samples was determined by SEM-EDS analysis. The effects of adsorption and photocatalytic activity of the prepared TiO2 samples were evaluated by the degradation of ciprofloxacin (CIP) as an emerging organic pollutant (EOP) under UV-A light (365 nm). The results of the photocatalytic activity of the synthesized TiO2 nanoparticles were compared to the benchmark Degussa P25 TiO2. Kinetic parameters of adsorption and photocatalysis were determined and analyzed. It was found that crystalline TiO2 nanoparticles with the highest specific surface area, the lowest energy band gap, and the highest photocatalytic degradation were the samples synthesized at 200 °C for 10 min. The results indicate that CIP degradation by all TiO2 samples prepared at 200 °C show a synergistic effect of adsorption and photocatalytic degradation in the removal process.