Improved Adsorption Capability Research Articles

MnO Modified Porous Carbon with Improved Adsorption Capability and Promoted Redox Kinetics in Lithium‐Sulfur Batteries

AbstractLithium‐sulfur (Li−S) batteries are recognized as one of the most promising next‐generation battery systems. However, the severe shuttle effect poses a crucial challenge for its large scale application. Herein, through simple freeze‐drying and subsequently annealing, the MnO was utilized to modify porous carbon and thereby form stable bond order toward lithium polysulfides (LiPSs), thus inhibiting the shuttle effect. Besides, the MnO nanoparticles can increase the reaction sites, accelerate the kinetic conversion of LiPSs, facilitate the formation and decomposition of Li2S during discharging and charging. Benefit from the merits of MnO mentioned above together with the physical confinement derived from porous carbon, the Li−S battery assembled with S@MnO−C cathode delivers excellent performance both in rate capacity and long‐cycling, with a high capacity of 555 mAh g−1 after 200 cycles at 0.3 C. This work broadens the potential and enlightens the strategy for designing efficient cathodes toward Li−S sulfur batteries.

Enhanced VOCs adsorption on Group VIII transition metal-doped MoS2: A DFT study

Volatile organic compounds (VOCs) represent a significant category of toxic and harmful air pollutants. Among the various abatement techniques available for VOCs, adsorption technology is widely recognized as a cost-effective solution. In this study, density functional theory (DFT) was employed to calculate and compare the adsorption capacities of six typical VOCs on pristine MoS2 and MoS2 modified with Group VIII (MVIII) transition metals atoms. It is found that MVIII-MoS2 monolayer demonstratesa significant enhancement in adsorption capabilities for VOCsrelative to pristine MoS2. Among these Group VIII transition metals atoms, Fe, Ru and Os atoms exhibited the most significant VOCs adsorption enhancement, with Fe atoms demonstrating a particularly pronounced effect. This suggests a synergistic interaction between the metal dopants and the substrate. Density of states (DOS) and charge density difference analyses provided further insights into the mechanisms underlying improved adsorption capability. Interestingly, the introduction of MVIII atoms results in the emergence of a novel state density within the surface state of MoS2, thereby facilitating enhanced electron transfer between VOCs and the substrate. Charge density difference calculations further corroborated these findings, with certain configurations exhibiting significant electron cloud overlap. Such modification leads to more active electron transfer, thereby increasing the substrate’s affinity for VOC molecules and consequently improving the adsorption efficiency. The findings not only enhance the comprehension of VOC adsorption mechanisms on MoS2 but also underscore the potential of metal-doped two-dimensional materials for environmental applications.

Conversion of char from pyrolysis of plastic wastes into alternative activated carbons for heavy metal removal

The valorization of post-consumer mixed plastics in pyrolysis processes represents an abundant reservoir of carbon that can be effectively converted into useful chars. This process not only holds appeal in terms of improving plastic waste concerns but also contributes to the reduction of greenhouse gas emissions, thus aligning with the principles of a circular economy paradigm. In this study, the char produced from the pyrolysis of post-consumer mixed plastic waste has been activated with Na2CO3, KOH, NaOH, and K2CO3 to improve the textural, structural, and composition characteristics, leading to improved adsorption capability. These characteristics were studied by N2 adsorption-desorption isotherms, scanning electron microscopy, elemental and immediate analysis, and X-ray photoelectron spectroscopy. The developed surface area (SBET) was 573, 939, 704 and 592 m2 g−1 for Na2CO3, KOH, NaOH and K2CO3 activated carbons, respectively. These activated chars (ACs) were tested for the adsorption of heavy metals in both synthetic waters containing Pb, Cd, and Cu and industrial wastewater collected at an agrochemical production plant. Na2CO3-AC was the best performing material. The metal uptake in synthetic waters using a batch set-up was 40, 13 and 12 mg g−1 for Pb, Cd and Cu. Experiments in a column set-up using Na2CO3-AC resulted in a saturation time of 290, 16, and 80 min for Pb, Cd, and Cu synthetic waters, respectively, and metal uptakes of 26.8, 4.1, and 7.9 mg g−1, respectively.The agrochemical effluents, containing mainly Cr, Cu, Mn, and Zn were tested in a plug-flow column. The metal uptake notably decreased compared to synthetic water due to a competition effect for active sites.

Aminobenzoate-defected UiO-66(Zr)–NH2 frameworks: Scalable synthesis and characterizations for adsorptive denitrogenation from model fuel

In this work, imperfection UiO-66-NH2 frameworks (AUiO-66-NH2) were engineered and scalably produced by a continuous flow method with the assistance of 4-aminobenzoate (ABA) modulators. ABA modulators competed with MOF ligands to bond to Zr4+ clusters under continuous flow conditions, producing AUiO-66-NH2 frameworks containing aminobenzoate linkers and ligand-missing defects. The average ligand deficiency per Zr6 unit of defective AUiO-66(Zr)–NH2 framework ranged from 0.75 ∼ 2.36 upon changing ABA/H2N-BDC molar ratio and reaction temperature, thereby adjusting their porosity and exposing more metal open sites of Zr4+. The batch removal of N-containing compounds (NCCs), including quinoline (QUN) and 2-methyl pyrrole (MPR) in n-octane indicated that the ABA-modulated UiO-66-NH2 samples had improved adsorption capability compared to the perfect MOF. Noticeably, the adsorption performances were further enhanced by protonating 2.5AUiO-66-NH2 to 2.5AUiO-66-NH3+ owing to the synergetic effects of acid-base interaction, H-bonds, cation-π interactions, and π-π stacking interactions between adsorbent and adsorbate. Density functional theory (DFT) calculations further revealed that the NCCs preferably accumulated onto the protonated AUiO-66-NH3+ rather than AUiO-66-NH2. The AUiO-66-NH3+ exhibited adsorbing capacities of ∼204 mg/g and ∼275 mg/g for MPR and QUN, respectively, and obeyed the pseudo-second-order kinetic model. Finally, the continuous fixed-bed adsorptions of these NCCs in model fuel over the AUiO-66-NH3+ pellets (3 mm × 6 mm) showed that 1.0 g of adsorbent can purify with ∼28 L and ∼49 L liquid fuel containing MPR and QUN with a concentration of 1 mg L−1. These state that combining continuous-flow synthesis and defect engineering of the UiO-66-NH2 could be a promising strategy to produce efficient adsorbent materials for upgrading liquid fuel.

Hexavalent chromium removal from aqueous medium by ternary nanoadsorbent: A study of kinetics, equilibrium, and thermodynamic mechanism.

Although many studies have focused on chromium removal from aqueous media by ternary Nano adsorbents, still the integrated kinetics, equilibrium, and thermodynamic mechanisms of chromium removal remain unknown. Thus in this study, we have synthesized a novel ternary oxide nanocomposite comprising iron, manganese, and stannous (Fe2O3-MnO2-SnO2) in a facile method as a promising adsorbent for the removal of Cr(VI) from an aqueous medium. The Fe2O3-MnO2-SnO2 system was firstly characterized by FTIR, XRD, TGA, BET, and SEM/EDX. The effect of parameters, for instance, pH, temperature, initial Cr(VI) intensity, and adsorbent dose, have been examined to optimize the Cr(VI) adsorption performance. The adsorption of Cr(VI) onto Fe2O3-MnO2-SnO2 nanoadsorbent is associated with an adsorption/reduction mechanism. Using an initial Cr(VI) intensity of 50 mg L-1, 200 rpm agitation, 2.5-g L-1 of adsorbent, pH 2, 90 minutes adsorption time, and 298 K temperature, a maximum adsorption capability of 69.2 mg Cr(VI) g-1 for Fe2O3-MnO2-SnO2 was obtained. Models of pseudo-2nd-order kinetics and Langmuir's isotherm were best suited to the investigated data. Besides, thermodynamic parameters show that Cr(VI) adsorption onto Fe2O3-MnO2-SnO2 was random and dominated by entropy. The reusability of Fe2O3-MnO2-SnO2 was found to be consistently high (remaining above 80% for Cr(VI)) over four adsorption-desorption cycles. Chromium adsorption from the tannery wastewater was achieved 91.89% on Fe2O3-MnO2-SnO2. Therefore, Fe2O3-MnO2-SnO2 nanoparticles, being easy to be synthesized, reusable and having improved adsorption capability with higher surface area, could be a desirable option for removing Cr(VI) from aqueous environments.

Work function analysis of photo-enhanced triethylamine adsorption impact on Au embedded CeO2 coated ZnO hybrid nanostructures: An investigation by scanning kelvin probe

This article utilizes a scanning kelvin probe to examine the impact of visible light and volatile organic compounds (VOCs) on an organic/inorganic/noble metal hybrid sensing layer. ZnO/Poly/CeO2/Poly/Au hybrid nanostructures were prepared on ITO substrate by layer-by-layer coating technique. In this case, PAH and DS polymers act as binders. The assembly of Au nanorods (NRs) on the polymer-coated ZnO NRs incorporated with CeO2 nanoparticles (NPs) and its maximum absorbance in the visible light region were studied by the structural and optical characterizations, respectively. The hybrid sensor's optical properties allowed for sizable changes in contact potential difference (CPD) when exposed to light. Although a non-selective interaction was observed, the increased responsiveness to Triethylamine (TEA) under visible light creates coordination bonds between the hybrid molecules. Notably, the surface charge was tuned in the surface of the sensing layer by varying the surfactant to explore the TEA responsiveness. Intriguingly, ZnO/Poly/CeO2 (+) has demonstrated improved adsorption capability towards TEA under irradiation due to the surface oxygen vacancies compared to ZnO/Poly/CeO2 (-). Also, ZnO/Poly/CeO2 (+) exhibited higher selectivity at adsorbing TEA than either ethanol or n-hexane.

Fabrication of polyethyleneimine functionalized magnetite nanoparticles for recyclable recovery of fucoidan from aqueous solution

Fucoidan is a kind of natural water-soluble fucose-rich sulfated polysaccharide with promising applications in the food and pharmaceutical industry. However, the traditional methods for fucoidan recovery from aqueous solution are expensive, time-consuming, and environmentally unfriendly. In this work, polyethyleneimine functionalized magnetite nanoparticles (PEI-MNPs) with well-defined core-shell structures were prepared by a Layer-by-Layer (LbL) approach using sodium tripolyphosphate (STPP) as a cross-linker. The as-prepared PEI-MNPs showed improved adsorption capability towards fucoidan at pH 4–8 due to the high density of cationic groups on the surfaces and the absence of internal pores. It was found that the adsorption process of fucoidan onto PEI-MNPs can reach to equilibrium in 50 min at room temperature. The maximum qe derived from the Langmuir isotherm at room temperature was 169.1 mg per g at a pH of 7. A selective fucoidan capture over a model protein BSA can be realized by adjusting pH (6–8) and salt concentration (0.5–2.5 M). The PEI-MNPs loading with fucoidan can be isolated from the final products by a neodymium magnet and regenerated by 4 M NaCl solution as stripping reagent. Therefore, this novel kind of PEI-MNP could be a promising candidate for highly efficient and recyclable recovery of fucoidan from an aqueous solution.

PH shifting effect on anionic dye removal by surfactant-modified sugar beet pulp: Modeling of column studies

pH shifting effect on the adsorption of anionic RBB dye was tested by using untreated and CTAB-treated SBP as adsorbent in both batch and continuous systems. Characterization of the sorbents revealed the effects of surface modification. Enhanced binding sites and more porous surface structure resulted in improved adsorption capability. Flow rate and initial RBB concentration effects were tested in packed bed column. Optimum pH value of the adsorption, which was determined as 2.0 in the batch studies with untreated SBP, shifted to 8.0 with 20 g/L CTAB treated SBP. Experimental data in column studies showed the decreasing capacity with increasing flow rate and enhanced performance with increasing inlet RBB concentration for both sorbents. Maximum capacities of the columns were found as 36.9 and 2.6 mg/g with dried SBP at pH 2.0 and 8.0, respectively, at a maximum inlet RBB concentration of 500 mg/L and a minimum flow rate of 0.8 mL/min. The highest capacity value at pH 8.0 was found as 140.0 mg/g under the same operating conditions, which reveals positive effect of the treatment on adsorptive performance. Langmuir isotherm was found to be most convenient model for the all equilibrium cases in the column. Moreover, Thomas model accurately predicted the breakthrough curves of each system. This is the first study reporting the modeling data of an anionic dye adsorption in a packed bed column by using modified SBP.

Efficiently selective removal of Pb(II) by magnetic ion-imprinted membrane based on polyacrylonitrile electro-spun nanofibers

The development of membrane for heavy metal ion removal in water treatment is still impeded by low adsorption efficiency, poor selectivity, and deficient recyclability, which has gained great interests in both laboratorial research and industrial application. Herein, our aim is to fabricate the magnetic ion-imprinted PAN membranes (MII-PMs) based on polyacrylonitrile electro-spun nanofibers with improved adsorption ability, selectivity, and recyclability for efficient and selective removal of Pb(II) from water. The chemical structure and chemo-physical properties of the as prepared MII-PMs were characterized. Remarkably, in competitive adsorption experiment the MII-PMs demonstrated a much higher adsorption capacity towards Pb(II) than other interfering metal ions with the selective order of Pb2+>Cu2+>Mg2+>Co2+>Ni2+>Cd2+>Zn2+>Na+>K+. In investigation of the adsorption mechanism towards Pb(II), the equilibrium adsorption data of MII-PMs fitted better with Freundlich isotherm equation, and the kinetic parameters matched well with pseudo-second-order mode. In regeneration and reusability experiment, the MII-PMs could be regenerated with eluting solution and displayed good adsorption capacity towards Pb(II) during 6 adsorption–desorption cycles. Only small amount of Fe ions was leached out after the regeneration experiments. Generally, the as prepared magnetic ion-imprinted membrane with improved adsorption capability, high selectivity, and excellent reusability towards Pb(II) ions can be utilized as a promising and efficiently potential adsorbent in actual water treatment.

Improvement of U(VI) removal by tuning magnetic metal organic frameworks with amine ligands

A magnetic metal organic framework was finely tuned by abundant amine groups (Mag MOF-NH2) for the purpose of improving the U(VI) removal from solution. The Mag MOF-NH2 displays outstanding removal capacity (80 mg⋅g−1) to U(VI) (10 ppm, 400 mL) within 15 min. To illuminate the adsorption mechanism of Mag MOF-NH2, the microstructure, the magnetic property, chemical composition of Mag MOF-NH2 and the reaction system were characterized. The adsorption mechanism was systematically investigated. Equilibrium adsorption experiments verifies the improved adsorption capability from nearly 0 for MIL-101 to 82 mg⋅g−1 for Mag MOF-NH2, which could be explained mainly by the interaction between the amine groups and targeted ions. The effect of humic acid (HA) and coexisting ions on the U(VI) adsorption were also investigated. The Ca2+ and Mg2+ ions have passive impact on the adsorption and the high pH value can facilitate the process. Mag MOF-NH2 holds great potential for the practical application owing to the outstanding U(VI) removal and satisfied regeneration in simulative wastewaters.

Disulfide Cross-Linked Poly(Methacrylic Acid) Iron Oxide Nanoparticles for Efficiently Selective Adsorption of Pb(II) from Aqueous Solutions.

The efficient selectivity of heavy metal ions from wastewater is still challenging but gains great public attention in water treatment on a world scale. In this study, the novel disulfide cross-linked poly(methacrylic acid) iron oxide (Fe3O4@S-S/PMAA) nanoparticles with selective adsorption, improved adsorption capability, and economic reusability were designed and prepared for selective adsorption of Pb(II) ions in aqueous solution. In this study, nuclear magnetic resonance, dynamic light scattering, scanning electron microscopy, X-ray diffraction, vibrating sample magnetometry, and thermogravimetric analysis were utilized to study the chemophysical properties of Fe3O4@S-S/PMAA. The effect of different factors on adsorption properties of the Fe3O4@S-S/PMAA nanoparticles for Co(II) and Pb(II) ions in aqueous solution was explored by batch adsorption experiments. For adsorption mechanism investigation, the adsorption of Fe3O4@S-S/PMAA for Co(II) and Pb(II) ions can be better fitted by a pseudo-second-order model, and the adsorption process of Fe3O4@S-S/PMAA for Co(II) and Pb(II) matches well with the Freundlich isotherm equation. Notably, in the adsorption experiments, the Fe3O4@S-S/PMAA nanoparticles were demonstrated to have a maximum adsorption capacity of 48.7 mg·g–1 on Pb(II) ions with a selective adsorption order of Pb2+ > Co2+ > Cd2+ > Ni2+ > Cu2+ > Zn2+ > K+ > Na+ > Mg2+ > Ca2+ in the selective experiments. In the regeneration experiments, the Fe3O4@S-S/PMAA nanoparticles could be easily recovered by desorbing heavy metal ions from the adsorbents with eluents and showed good adsorption capacity for Co(II) and Pb(II) after eight recycles. In brief, compared to other traditional nanoadsorbents, the as-prepared Fe3O4@S-S/PMAA with improved adsorption capability and high regeneration efficiency demonstrated remarkable affinity for adsorption of Pb(II) ions, which will provide a novel technical platform for selective removal of heavy metal ions from actual polluted water.

One-step synthesis of nitrogen-doped sludge carbon as a bifunctional material for the adsorption and catalytic oxidation of organic pollutants

Nitrogen-doped carbon (NC) materials have been extensively investigated for their great potential applications in adsorption, catalysis, etc. Herein, we report a facile one-step pyrolysis process for NC synthesis using abundant bio-waste of excess sludge as carbon source and cheap precursor of urea as nitrogen source. The developed materials were evaluated for organic pollutants removal through adsorption and catalytic oxidation by peroxymonosulfate (PMS) activation. Experimental results demonstrated that nitrogen doping significantly affected the elemental composition and microstructure of NC, leading to improved adsorption capability as well as PMS activation activity for methylene blue (MB) removal. The adsorption capacity for MB reached 35.831 mg g−1 over NC-700 sample (NC prepared at 700 °C). In MB catalytic oxidation experiments, effects of sample calcination temperature, catalyst dosage, PMS loading, and co-existing ions were investigated. Under optimal reaction conditions, 98.70% of MB could be removed in 20 min. Through radical quenching and electron spin resonance (ESR) tests, it was confirmed that singlet oxygen (1O2) was the main reactive species for MB degradation. Additionally, NC-700 performed well in recycle studies without significant efficiency loss. Other typical organic pollutants including malachite green (MG), methyl orange (MO), bisphenol A (BPA), phenol (PE), and sulfamethoxazole (SMX) could also be removed using NC-700 as adsorbent and catalyst. These features manifest that excess sludge-derived NC could be a promising material for organic pollutants remediation.

Fabrication of carboxyl-functionalized polymer microtubes via RAFT copolymerization of diurea-type xerogel fibers and acrylic acid

A new diurea-type gelator was synthesized from 2-isocyanoethyl acrylate and 4′-diaminodiphenylmethane, which formed supramolecular gel in acetonitrile driven by hydrogen bonds. The xerogel fibers with a smooth lamellar structure were used as templates and monomer source in fabricating polymer microtubes via reversible addition-fragmentation chain transfer polymerization. Because of a very low solubility of the gelator, the polymerization in toluene gave no insoluble product. As suitable amount of methanol was used together with toluene, the polymerization was conducted successfully to obtain ribbon-like polymer tubes with smooth surface. Based on which, acrylic acid was further used as a co-monomer to form carboxyl-functionalized polymer tubes. The resulting products were characterized by multiple techniques. Compared with the ordinary polymer tubes, the carboxyl-functionalized polymer tubes exhibited much improved adsorption capability for methylene blue (MB) at pH 7 and the absorbed MB molecules could be released in both acidic water and acidic ethanol.

Facile fabrication of Shewanella@graphene core-shell material and its enhanced performance in nitrobenzene reduction

A novel Shewanella@graphene core-shell composite material was fabricated following one-step bioreduction of graphene oxide (GO) by Shewanella putrefaciens CN-32. The surface properties and microstructures were characterized by FTIR, TG-DTG, SEM and TEM, which indicate that GO was effectively reduced to rGO and subsequently loaded onto the outer surface of the microbe Shewanella. CLSM was performed to get insight into the growth of the bacteria after core-shell materials formation. The reduction properties of Shewanella@graphene materials were evaluated using nitrobenzene, a representative model pollutant, as an electron acceptor. The reduction efficiency of Shewanella was improved by strengthening the contact among electron donors, electron shuttles and electron acceptors and changed with the proportions of core-shell materials. The optimal proportion of the core-shell material was OD600 = 0.6:GO = 10 mg/L, which was enhanced by the wrapped rGO and improved adsorption capability. The reduction rate was elevated 30% in comparison with pure Shewanella. In addition, the core-shell material exhibited a favorable recycling performance, which can be reused for at least five times. Facile fabrication and enhanced reduction performance of Shewanella@graphene core-shell composite endows this material with considerable potential in environmental remediation.

Construction of CNCs-TiO2 heterojunctions with enhanced photocatalytic activity for crystal violet removal

In this study, CNCs-TiO2 heterojunctions were synthesized successfully via a two-step method. The obtained materials were systematically characterized by a series of technologies including XRD, TEM, HRTEM, FT-IR, XPS, UV-DRS, PL and EIS. Moreover, the photocatalytic activity of CNCs-TiO2 was evaluated by the photodegradation of crystal violet (CV) under UV and visible light irradiation. The results of characterization demonstrated that the CNCs-TiO2 heterojunctions were formed. For composite CNCs-TiO2, the anatase TiO2 was uniformly dispersed on the surface of CNCs with graphite structures via a new chemical bond, TiOC and the growth of crystalline grains was inhibited. The photo-absorbing range of TiO2 was extended to the visible light region after coupling with CNCs leading to the enhancement of light-harvesting ability. In addition, compared with pure TiO2 particles, the recombination of photoinduced electrons and holes was restrained. The photodegradation experiment indicated that the CNCs-TiO2 exhibited enhanced photocatalytic activity in contrast with TiO2 under UV and visible light irradiation, which was the result of the combined action of improved adsorption capability, enhanced light harvesting performance and efficient charge separation and transfer. The degradation of CV in the photocatalytic system followed the pseudo-first-order kinetics model. Lastly, the main mechanism for the enhanced photocatalytic activity of CNCs-TiO2 was significantly put forwarded.

One‐pot Synthesis of Novel Composite@Composite‐Typed Core@Shell Nanostructures and the Adsorption Property for Dye Wastewater

AbstractIn this work, the novel composite@composite‐type core@shell nanostructures, i.e. Na0.5Ce0.5MoO4‐MoS2@Na0.5Ce0.5MoO4‐MoS2, have been synthesized via one‐pot hydrothermal method. The core and shell are both composed of Na0.5Ce0.5MoO4‐MoS2 but with different mass ratios of Na0.5Ce0.5MoO4 to MoS2, which are obviously different from the commonly reported core@shell nanostructures with the single‐component core and the single‐component shell. Besides, it is found that for single dye solution, 20 wt% core@shell sample has an significantly improved adsorption capability for rhodamine B (RhB), but a poor adsorption capability for methyl orange (MO) dye. In RhB‐MO mixture solution, the adsorption of RhB has been greatly promoted by MO. In addition, Cr(VI) ion has significantly decreased the adsorption capacity of RhB; meanwhile, K(I) ion can slightly promote MO adsorption. This work provides a simple preparation approach to the new composite‐type core@shell nanostructures, and can help us to understand the adsorption processes for practical wastewaters.

Optimized porous clay heterostructure for removal of acetaldehyde and toluene from indoor air

Adsorption is the most widely used technology for the removal of indoor volatile organic compounds (VOCs). However, existing adsorbent-based technologies are inadequate to meet the regulatory requirement, due to their limited adsorption capacity and efficiency, especially under high relative humidity (RH) conditions. In this study, a series of new porous clay heterostructure (PCH) adsorbents with various ratios of micropores to mesopores were synthesized, characterized and tested for the adsorption of acetaldehyde and toluene. Two of them, PCH25 and PCH50, exhibited markedly improved adsorption capability, especially for hydrophilic acetaldehyde. The improved adsorption was attributed to their large micropore areas and high micropore-to-mesopore volume ratios. The amount of acetaldehyde adsorbed onto PCH25 at equilibrium reached 62.7 mg·g−1, eight times as much as the amount adsorbed onto conventional activated carbon (AC). Even at a high RH of 80%, PCH25 removed seven and four times more of the acetaldehyde than AC and the unmodified raw PCHs did, respectively. This new PCH optimized for their high adsorption and resistance to humidity has promising applications as a cost-effective adsorbent for indoor air purification.

Photocatalytic-based strategies for H 2S elimination

The mechanism of H 2S elimination in gas phase by means of heterogeneous photocatalysis was investigated. The main drawbacks for a real application were identified to be related to the nature of the reaction products: SO 2 is toxic, corrosive and malodorous, and SO 4 2− accumulates on the photocatalyst surface leading to deactivation. In order to face this challenge, supported photocatalysts with different properties were synthesised to investigate several strategies according to the photocatalyst selectivity. On one hand, two different approaches for coupling adsorption and photocatalysis have been proposed to solve the problem of SO 2 release and prolong the catalyst lifetime. First, porous and SO 2-selective photocatalysts were synthesised by sol–gel with the help of surfactants. These materials presented good conversion values and suffered slower deactivation; an external adsorption unit might retain the SO 2 produced. Alternatively, improved adsorption capability of the photocatalyst was obtained through the synthesis of coated and incorporated hybrid TiO 2–SiMgOx composites, whereby SO 2 release was avoided and the lifetime of the photocatalyst prolonged. The combination in a hybrid material of an efficient photocatalyst and an adsorbent that may act as support constitutes a promising alternative for H 2S elimination due to the coupling of photocatalytic and adsorptive properties. On the other hand, photocatalyst regeneration was achieved by rising with water, which recovered the active sites. Moreover, when a 1 M KOH solution was used in the process, the creation of new basic active sites resulted in an increase of the photocatalytic activity, even higher than for the fresh material.