The catalytic conversion of CO2 into methane (CH4) offers a sustainable solution to the worsening global warming scenario, especially for controlling CO2 levels. This study reports silicalite-1 supported Ni catalysts with different loadings for CO2 conversion to CH4, prepared via wet impregnation. The X-ray diffraction pattern revealed an increase in crystallite size at higher Ni loadings, which was further supported by N2 sorption, where the specific surface area and microporosity of the catalysts were decreased. There was a slight shift in the reducibility of the catalysts, potentially indicating the impact of loading on dispersion and spatial distribution. The catalyst performance was evaluated over a range of temperatures at 5 bar and a GHSV of 20,000 mL gcat−1 h−1. Surprisingly, the Ni(5)@Silicalite-1 exhibited higher CO2 conversion efficiency across the range of temperatures compared to Ni(10)@Silicalite-1. The NiO(5)@Silicalite-1 demonstrated a maximum CO2 conversion of 88% at 450 °C, which was approximately 14% higher than that of the catalyst with a 10 wt.% loading. Notably, the CH4 selectivity pattern was quite identical across the catalysts, underscoring that the reaction pathways were unaffected by the loadings. The higher performance of NiO(5)@Silicalite-1 could be ascribed to smaller NiO crystallites and improved textural properties.

Here, we introduce three new halogen-free salts based on the green, sustainable, and hydrolytically stable saccharinate (Sac) anion, and their deep eutectic solvents (DESs) with ethylene glycol (EG). All the three salts exhibit distinct and well-defined thermal behaviors, ranging from ionic plastic crystals (IPCs) to supercooled liquids and classical ionic liquids (ILs). In contrast, their corresponding DESs display no detectable thermal events, a clear indication of successful DES formation, which is well supported by FTIR spectroscopy and suggests that EG interacts with the -CO and - SO2 groups of the Sac anion. DES with [EMPip][Sac] offers superior ion transport and electrochemical properties, supporting a voltage range up to 5.7 V, and as an electrolyte in a symmetric supercapacitor, a specific capacitance of 46.5 F g- 1 at 5 mV s- 1, an energy density of 9.9 Wh kg- 1, and power density of 1022 W kg- 1, at a current density of 0.2 A g- 1. The capacitor retained 99 % of its initial capacitance after 20,000 cycles at ambient temperature. Altogether, these halogen-free DES electrolytes offer promising electrochemical properties, making them ideal electrolytes for supercapacitors operating at ambient temperatures over a wide potential range.

Here, we present carbon anode materials derived from birch biomass (BCAM) with hierarchical micro-mesoporous structure, largely amorphous carbon framework and abundant active sites for lithium storage and efficient ion-transport - prepared through phosphoric acid activation followed by high-temperature pyrolysis at 1000 °C. BCAM materials deliver a reversible capacity of 915 mA h g-1 at 1C after 1000 cycles, maintain 412 mA h g-1 after 2000 cycles at 2.5C, and retain 235 mA h g-1 after 5000 cycles at 5C with ca. 100% coulombic efficiency. As for comparison, a cell made with commercial graphite as also tested, the results showed a reversible capacity of 365 mA h g-1 at 1C after 400 cycles, a much lower capacity than that of BCAM anode material. Kinetic analysis indicates a substantial pseudocapacitive contribution, particularly at higher scan rates, which supports fast charge-discharge behavior. In addition, electrochemical impedance spectroscopy reveals low charge-transfer resistance and favorable lithium-ion diffusion kinetics. In total, these birch-derived carbons provide a steppingstone in robust, low-cost, and environmentally benign anode materials, and offer a promising route towards long-life time and sustainable lithium-ion batteries (LIBs).

Fluorine-free supercapacitor (SCs) electrolytes are desirable to minimize environmental impact and toxicity while maintaining high electrochemical performance and long-term sustainability. Here, we introduce the new class of fluorine-free ionic liquids (ILs) engineered around the unique electron-deficient triazine-derived anion, 4,6-diethoxy-2-oxo-2H-1,3,5-triazin-5-ide (DET), coupled with n-tetrabutyl- phosphonium and ammonium cations. Both the ILs exhibit distinct and well-defined thermal behaviors, the former behaves as a glass-forming liquid, that is, have glass transition at -63 degrees C, while the latter exists as a supercooled liquid with complex thermal events and is ca. 90 K less thermally stable. We find relatively weaker cation-anion interactions - well supported by the FTIR data - and, thus higher ionic conductivity and higher electrochemical stability, with supporting voltage range up to 4.4 V, for (P-4444)(DET) than in (N-4444)(DET). (P-4444)(DET) as SCs electrolyte delivers excellent capacitive performance within the 2.0 V window at 30 degrees C and 60 degrees C. The device achieved areal capacitance of 78 mF cm(-2) (at 0.146 mA cm(-2)) and gravimetric capacitance of 60.6 F g(-1) (at 0.15 A g(-1)) at 60 degrees C and delivered an energy density of 34.6 Wh kg(-1) and the power density of 1873 W kg(-1) while maintaining similar to 94% capacitance retention and similar to 98% coulombic efficiency after 1000 cycles. SCs.

This work reports the design of binary and ternary BiOI-based composites incorporating the metal-organic framework CAU-17 and the amine-functionalized microporous organic polymer MOP-CH(2)EDA for the removal of ciprofloxacin (CIP) from water. The materials were synthesized via an in situ solvothermal approach and systematically characterized to establish structure-property relationships. The results reveal that adsorption and photocatalysis act as coupled and sequential processes, rather than independent pathways, with the polymer component enhancing CIP pre-concentration and the BiOI/MOF interface governing photodegradation. The ternary composite BCM-10% exhibited the best performance, achieving up to 80% CIP removal under simulated solar irradiation. Scavenger experiments indicate that & centerdot;O-2(-) is the dominant reactive species, while photogenerated holes also contribute significantly. The degradation process is strongly influenced by pH, reflecting the interplay between catalyst surface properties, reactive oxygen species generation, and CIP speciation. HPLC-MS analysis confirms the formation of multiple intermediates and highlights the complexity of the degradation pathways. Despite the improved performance of the ternary composites, the overall activity remains moderate compared to state-of-the-art photocatalysts, underscoring the limitations of current BiOI-based systems. The results emphasize that apparent kinetic behavior is strongly affected by adsorption contributions, complicating direct comparison with literature data. This study provides new insight into the design of multifunctional materials for water treatment, highlighting the importance of adsorption-photocatalysis synergy and the need for more rigorous and standardized evaluation of photocatalytic systems.

Herein, we introduce fluorine‐free ionic liquids (ILs) and electrolytes based on electron‐deficient triazine, 4,6‐Diethoxy‐2‐Oxo‐2H‐1,3,5‐Triazin‐5‐ide, (DET), ‐anion coupled with oligoether‐functionalized pyrrolidinium and imidazolium cations. Having the same anion, imidazolium IL show slightly better thermal and electrochemical stabilities, but lower ion transport and higher glass transition temperature, T g , compared to its pyrrolidinium analog. Doping neat ILs with 20% lithium DET salt and creating lithium‐conducting electrolytes increases the overall thermal and electrochemical stabilities but decreases the ion mobilities. As the lithium battery electrolyte, Li∥Li symmetric cells confirm stable and reversible Li cycling for both electrolytes, with the imidazolium system showing lower polarization and midpoint hysteresis, indicating faster interfacial kinetics and reduced resistance; correspondingly, it also delivers narrower charge–discharge plateaus and improved voltage stability in Li∥LFP half‐cells. For imidazolinium‐based electrolytes, with the addition of 5 wt% vinylene carbonate (VC), the Li∥LFP cells exhibited excellent rate capability from 0.1C to 1C at 60 °C and maintained stable cycling around 200 cycles at 0.1C with nearly 99% capacity retention and coulombic efficiency, demonstrating enhanced interfacial stability and efficient lithium‐ion transport.

Removal of pharmaceuticals from wastewater remains a major environmental challenge, requiring efficient and selective Advanced Oxidation Processes (AOPs). Catalytic and non-catalytic ozonation was investigated in a laboratory-scale reactor under optimized flow conditions (500-750 mL min-1, 98 % O2 feed). Ozonation kinetics of active pharmaceutical ingredient mixtures (APIs) consisting of ibuprofen (IBU), diclofenac (DCF), carbamazepine (CBZ), sulfadiazine (SDZ), and sulfamethoxazole (SFX) (40 mg L-1 each) - was investigated using iron-modified zeolite catalysts, Fe-H-Y and Fe-H-Beta, under semi-batch operations (0.5 g catalyst, 20 degrees C) in order to correlate degradation and mineralization efficiency with catalyst structure, acidity, and stability. Both catalysts significantly improved the ozone utilization compared to non-catalytic ozonation. Interestingly, Fe-H-Y accelerated initial degradation rate, while the use of Fe-H-Beta resulted in the highest level of mineralization. Adsorption-desorption analysis revealed that the molecular size and polarity controlled the interactions between the pharmaceutical and the catalyst: smaller polar compounds (SDZ, SFX) exhibited stronger adsorption on the catalyst, while bulkier molecules (DCF, IBU) were restricted to external surfaces. Post-reaction characterization confirmed that the Fe-H-Y retained more surface area and exhibited lower Fe leaching, while Fe-H-Beta showed significantly higher carbon deposition. Overall, Fe-H-Y combined rapid kinetics and structural stability, while Fe-H-Beta provided higher mineralization, at the expense of more extensive fouling. The study demonstrated that optimized ozonation conditions, coupled with tailored zeolite catalysts, markedly improve the oxidation efficiency and long-term performance in the oxidation of pharmaceuticals.

Catalytic conversion of carbon dioxide (CO 2 ) into useful chemicals such as methane (CH 4 ) is a promising carbon utilization method that effectively mitigates CO 2 and partially meets energy needs. The characteristics of commonly used nickel (Ni) supported meso/microporous catalysts for CO 2 methanation can be tailored by tuning the structural properties of the support and adding promoters. This work investigated the Ni supported over hierarchical zeolite 13X (h13X) and incorporated with different promoters (Mg, Ca, Ce, and La) developed using the wet‐impregnation method. The catalysts were thoroughly characterized using SEM, EDS, XRD, H 2 ‐TPR, CO 2 ‐TPD, thermogravimetric analysis (TGA), X‐ray photoelectron spectroscopy (XPS), and N 2 sorption and desorption techniques and evaluated for CO 2 methanation. The impact of promoters on the characteristics of the catalysts was observed with improved surface basicity in CO 2 ‐TPD and metal‐support interaction in H 2 ‐TPR analysis. Among the promoted catalysts, the NiLa/h13X catalyst exhibited the highest catalytic activity with a maximum conversion of 76% and CH 4 selectivity of 98.5% at 400°C and 20 bar at GHSV of 60,000 mL g cat −1 h −1 , respectively. Regarding stability, the Mg‐promoted catalyst exhibited better stability during 24 h of reaction than other catalysts, demonstrating better resilience against deactivation. The enhanced performance of the NiLa/h13X catalyst could be credited to the increased surface basicity, high surface area, and dispersion. This study highlights the potential of hierarchical porous zeolites for CO 2 methanation and other heterogeneous reactions.

[This corrects the article DOI: 10.1021/acssusresmgt.4c00258.].

Water pollutants such as synthetic dyes can cause significant problems for human health and ecosystems due to their chemical properties and environmental interactions. Contamination of surface and underground water caused by the discharge of synthetic dyes is a widespread problem that arises primarily from industrial activities such as textile manufacturing, leather processing, paper production, and plastics industries. Since adsorption is one of the most efficient and reliable methods to remove pollutants from water, in this work, pine tree logging residues (LR) were used to produce boron/sulfur chemically modified biochars with superior adsorption performance and recyclability. The biochars were produced using a two-step pyrolysis procedure with potassium hydroxide as a chemical activator. The specific surface areas (B.E.T.) of the biochars were 2645 m2 g-1 for the boron-treated biochar (LR-Boron), 2524 m2 g- 1 for the sulfur-treated (LR-Sulfur), and 3141 m2 g- 1 for the control biochar (LR-Control, without boron or sulfur), respectively. The LR-Boron biochar showed an exceptional degree of graphitization of (ID/IG=0.45), while the LR-Sulfur biochar displayed an ID/IG= 1.02; for comparison, the LR-Control exhibited an ID/IG= 0.81, showing that the sample subjected to boron treatment created carbon- rich in graphitic structures. The three biochars were evaluated as adsorbents for removing reactive black-5 azo dye (RB-5) from water and mixtures of several dyes in synthetic aqueous effluents. The adsorption data showed that all carbons exhibited outstanding RB-5 removal performance. Kinetic measurements were well fitted by the Avrami fractional order model, and the LR-sulfur carbon displayed the fastest adsorption kinetics. Isotherm measurements were well fitted by the Liu model, with a theoretical Qmax of around 1419 mg g- 1 (LR-Control), 1586 mg g-1 (LR-Boron), and 1766 mg g-1 (LR-Sulfur) at 316 K. The presence of sulfur-functional groups on the LR-Sulfur biochar surface was probably the reason for the superior adsorption performance of this biochar. Both sulfur and boron-treated biochars exhibited higher regeneration potentials, maintaining around 60-67 % removal capacity after 7 cycles compared to 35 % for the LR-Control biochar. Thermodynamic adsorption studies showed that the adsorption process was endothermic, favorable, and compatible with physical adsorption. All produced biochars were highly efficient for removal of pollutants from concentrated synthetic effluents.

The transition to sustainable energy systems requires efficient catalysts capable of upgrading biomass into liquid fuels and platform chemicals to meet future energy demands. Metal oxides, as supports in bifunctional catalysts, are pivotal due to their ability to provide active sites, create oxygen vacancy defects, and facilitate electron transfer. While these properties are well-studied in the presence of metal nanoparticles, the intrinsic activity and surface properties of stand-alone oxide supports remain underexplored. This study investigates the role of bare metal oxides (TiO2, ZrO2, and Al2O3) in the direct vapor upgrading of beechwood biomass vapors via a two-stage process comprising a non-catalytic hydropyrolysis step followed by ex-situ catalytic upgrading. The performance of metal oxides was compared with non-metal oxide such as SiO2. Through extensive characterization (H2-TPR, NH3-TPD, O2-TPD, CO2-TPD, BET, XRD, and Pyridine-FTIR), we establish that the combination of high weak acidity, low strong basicity, and reducibility of TiO2 results in superior catalytic performance. Ex-situ upgrading over TiO2 achieves the lowest oxygen-to-carbon ratio (O/C = 0.09) in bio-oil, the highest C2+ fraction (98.7 %), and the largest C8-C16 fraction (49.9 %), while minimizing light molecule formation (16.5 %). Binding energy analyses further reveal that weak adsorption of model compounds (acetone, acetic acid, guaiacol) occurs on the TiO2 (101) surface compared to other oxide surfaces, highlighting its exceptional properties for deoxygenation and C-C coupling. This work establishes the first comprehensive correlation between the catalytic performance of oxide supports and their surface properties using actual biomass feedstock, thus offering valuable insights for designing advanced catalysts for biomass upgrading.

Herein, a Ru-decorated carbon material bearing unique surface chemistry (Br & oslash;nsted acidic phosphate groups, Lewis basic N-groups and oxygen functional groups) is shown to exhibit exceptional activity, selectivity and stability upon direct hydrogenation of aqueous levulinic acid (LA) (0.47 M and 0.95 M) to gamma-valerolactone (GVL) under mild conditions (25-95 degrees C and 3.5-5 bar). The multifunctional Ru/carbon catalyst outperformed the bifunctional Ru/NbOPO4, and blended (physically mixed) catalytic systems comprising of commercial Ru/carbon (hydrogenation catalyst) and NbOPO4/Amberlyst 15 (acid promoter/co-catalyst). The material also demonstrated remarkable stability for energy efficient GVL production in a fixed-bed reactor under continuous flow conditions, maintaining stable GVL productivity during 52-day time on stream operating at 3.5-5 bar, 80-95 degrees C and low H2/LA ratio (4-17:1 mol/mol). The exceptional catalytic performance and long term stability of the multifunctional carbocatalyst was attributed to the presence of highly active Ru(0) nanoparticles stabilized on N-doped carbon framework and acidic phosphates and RuOx/RuO2 sites, which promote LA hydrogenation and intramolecular esterification of 4-hydroxypenatonnic (4-HPA) in tandem, affording a high GVL selectivity. The catalyst's combination of high productivity, long-term stability, and ability work under intensified setting in mid conditions highlight its potential for energy efficient GVL production at large scale.

NbOPO4 supported TiO2 materials were demonstrated to be excellent catalysts for selective conversion of C6carbohydrates to 5-hydroxymethylfurfural in an environmentally benign dimethyl carbonate-water solvent system. The materials presented high activity and excellent stability in sub-critical water conditions (upto 180 degrees C and 20 bar), enabling continuous 5-hydroxymethylfurfural production from highly concentrated sugars (35 wt% fructose, glucose and glucose:fructose mixtures) in a micro fixed-bed reactor. The high catalytic activity (6-27.3 KgHMFKgCat - 1day- 1) and good-to-excellent HMF selectivity (55-91 %) and exceptional hydrolytic stability and regenerability observed under process conditions was attributed to a highly crystalline NbOPO4 phase with Q2 and Q3 phosphates stabilized on a TiO2 framework with tunable acidity (0.11-0.52 mmolH+g- 1 and Br & Oslash;nsted/ Lewis ratio) and acidic strength comparable to bulk-NbOPO4. Furthermore, our experiments also revealed the importance of organic solvents in modulating catalyst acidic properties, particularly the strength of Br & Oslash;nsted acid sites which, in turn, influenced the HMF productivity.

Biochar has recently been identified as a potential solution for the remediation of organic micropollutants from contaminated water. Herein, we have assessed the potential mitigation of per- and polyfluoroalkyl substances (PFAS) by means of biochar adsorption as a green alternative to coal-based sorbents for PFAS-polluted stormwater systems. For this purpose, 13 biochar materials (originating from diverse feedstocks as well as intended for both commercial and research purposes) were initially screened for PFAS remediation capabilities in static flow systems. These experiments pointed to biochar sorption as a promising strategy for PFAS remediation, with some materials showing removal efficiencies of around 99% after 7 days of exposure. Though not all of the biochar materials tested performed equally, differences could be observed. As a next step, five biochar materials were studied under constant-flow column experiments for a duration of 69 days using real stormwater spiked with PFAS. Results showed that vast differences could be observed for the retention rates of the tested PFAS contaminants, with estimated bed volumes for an 80% breakthrough ranging from, for example, 13-60 for perfluorobutanesulfonic acid and from 4 to 53 for perfluoropentanoic acid. In terms of the PFAS backbone, both the static and dynamic flow experiments highlighted that long-chain PFAS showed stronger sorption onto the biochar surface than short-chain PFAS; however, no relevant impact could be identified in terms of the PFAS functional group. Overall, biochar is emerging as a promising and environmentally friendly approach for removing PFAS from contaminated stormwater.

Lignin valorization has attracted significant attention in recent years due to its abundance and potential as a renewable organic carbon resource to produce a variety of value-added chemicals and fuel additives. Catalytic upgrading of lignin faces challenges due to its complex structure and an active catalyst with selective surface properties is needed to break the stable C-O and C-C interunit linkages. In the present work, we developed a series of multifunctional Ru/NbOPO4/TiO2 catalysts with varying surface acidic properties and explored their potential upon hydrogenolysis of lignin model compound eugenol. Textural and surface acidic properties of the prepared materials were studied by means of different techniques such as N2-physisorption, NH3-TPD, XRD, SEM-EDS, Raman spectra, FT-IR, and TEM. Our catalytic results revealed synergistic role of acid and metal sites upon catalyst performance, whereupon high yields of hydrocarbons (86.9-100 wt.%) were obtained with selective cleavage of the methoxy and hydroxy groups under milder conditions. A kinetic study further identified the reaction mechanism and determined a rate law and partial reaction orders. This research advances the understanding of catalyst design for upgrading of the lignin or lignin monomers into value added chemicals. and on the other hand, contributes to sustainable development by maximizing biomass usage and providing environmentally friendly alternatives in renewable energy.

The current study presented a porous liquid (PL) prepared from propylene glycol-based deep eutectic solvent (DES) and hyper-crosslinked polymers (HCP) that are liquids over wide temperature ranges, including ambient temperature. It was shown that the solvent molecules are too large to penetrate the pores of HCP, so the PL is maintained as a suspension with permanent free volume for several months and can absorb large amounts of gases. This study marks the pioneering use of DESs as the liquid medium, replacing ionic liquids due to their closely matched properties. The structural features of both DES and HCP are retained; the increase in CO2 absorption capacity compared to pure DES is due to the presence of a porous solid and is proportional to the amount of solid. The absorbed CO2 amount rises from 1.0105 mmol center dot g(-1) in pure DES to 1.3232, 1.6027, and 1.2168 mmol center dot g(-1) in PL-1, PL-2, and PL-3, respectively. Thermodynamic analysis revealed that the enthalpy of gas absorption allows straightforward regeneration of the PLs in the studied cases. The investigated PLs show great potential as gas absorbents, with the incorporation of just 0.5 wt% of porous polymer material leading to an impressive increase in solvent absorption capacity, up to 59 %.

Two novel, structurally different perfluoroalkyl ionic liquids with bicyclic guanidinium cation have been synthesized and applied as a surfactant component for selected active pharmaceutical ingredients (APIs). The addition of perfluoroalkyl ionic liquid to hydrophobic APIs significantly improves their solubility. One of the key and characteristic properties of guanidine derivatives is their strong ability to chemisorb protons (proton affinity). This property enables them to form stable ionic-type aggregates (adducts) with selected hydrophobic APIs containing carboxylic groups. Therefore, these new compounds are, in fact, API-IL ionic adducts formed as hydrogen bond donor-acceptor systems. The obtained adducts are characterized by significantly better solubility than the initial APIs. The presence of perfluoroalkyl chains with unique surface-active properties enables to obtain a solubility of new adducts to reach level sufficient for typical ophthalmic preparations. (e.g., eye drops or lens care). The ionic API-IL adducts obtained in the described studies can be considered as examples of a new class of active derivatives with pharmaceutical potential.

Ensuring effective monitoring of methotrexate (MTX) levels in the bloodstream of cancer patients undergoing high-dose methotrexate chemotherapy is crucial to prevent potentially harmful side effects. However, the absence of portable analytical devices suitable for point-of-care bedside monitoring has presented a significant obstacle to achieving real-time MTX monitoring. In this study, we developed an impedimetric immunosensor that doesn't require reagents for measuring MTX levels in undiluted human blood serum. This reagentless approach simplifies the assay process, enabling rapid and straightforward MTX quantification. The immunosensor transducer was fabricated by electrodepositing conductive network of porous multiwalled carbon nanotube@polypyrrole/polytyramine on screen-printed gold microchip electrode (SP-Au/MWCNT70@PPy-PTA). Polyclonal anti-MTX antibodies were immobilized on the film, acting as the immunorecognition element. Nonspecific binding was prevented by blocking the transducer interface with denatured bovine serum albumin (dBSA) fibrils, resulting in SP-Au/MWCNT70@PPy-PTA/anti-MTXAb|dBSA film electrode. When MTX binds to the SP-Au/MWCNT70@PPy-PTA/anti-MTXAb|dBSA interface, the film conductance and electron transfer resistance changes. This conductivity attenuation allows for electrochemical impedimetric signal transduction without a redox-probe solution. The electrochemical impedance spectroscopy (EIS) results showed increased charge transfer resistance and phase angle as MTX concentrations increased. The SP-Au/MWCNT70@PPy-PTA/antiMTXAb|dBSA demonstrated high sensitivity, with a linear response from 0.02 to 20.0 mu M and a detection limit of 1.93 nM. The detection limit was 50 times lower than the intended safe level of MTX in human serum. The immunosensor exhibited minimal cross-reactivity with endogenous MTX analogs and serum proteins. The SP-Au/ MWCNT70@PPy-PTA/anti-MTXAb|dBSA immunosensor presents a simple and rapid method for therapeutic drug monitoring compared to traditional immunoassay systems.

The charge generation properties of solid, UV-cured and charge-separated ionic liquid electrets as energy harvesters.

Poly-(3-hydroxybutyrate), PHB, is a bacterial polyester in industrial demand as a biodegradable alternative to fossil-derived nondegradable plastics. Moreover, apart from being used directly as a bioplastic, valorization of PHB to its monomer building blocks and other value-added chemicals is feasible but less explored. In this study, Bronsted acid ionic liquid (BAIL) catalyzed depolymerization of PHB was investigated as a highly selective route to 3-hydroxybutyric acid, 3-HBA. The hydrolysis of PHB to 3-HBA was performed in a biphasic solvent medium composed of methyl isobutyl ketone (MIBK) and water, where the organic phase had dual roles as an efficient medium for dissolution of the polymer and as solvent for the monomeric products, which were enriched in this phase after cooling, with the Bronsted acid ionic liquid (BAIL) catalyst partitioned into the aqueous phase for facile recycling. The effects of reaction parameters, including the temperature, types of IL in terms of cations and anions, and the amount of water and IL, were studied to assess the yield of 3-HBA. Furthermore, protic acids such as sulfuric acid, methanesulfonic acid, and p-toluenesulfonic acid (p-TsOH) were also applied for comparison as acid catalysts for the hydrolysis of PHB to 3-HBA. Among the tested catalysts, the ILs containing the p-TsO- as anion as well as p-TsOH alone were found to be highly selective in promoting hydrolysis to 3-HBA, with complete depolymerization of PHB at >90% yield of 3-HBA in 4 h at 120 degrees C using a BAIL with sulfobutylated 1-methylimidazolium as the cation component and p-TsO- as the anion ([ImSO(3)H(+)][p-TsO-]). Although the use of p-TsOH as the sole catalyst also yielded efficient PHB hydrolysis with high reaction rates, it had a disturbing effect on the biphasic MIBK-water system by forming a single-phase reaction mixture at high 3-HBA yields, obstructing the recoveries of the products as well as the catalyst. In contrast, the biphasic reaction mixture remained intact when using IL as catalyst, which allowed facile and efficient separation of the product from the catalyst. Both the 3-HBA and the [ImSO(3)H(+)][p-TsO-] IL were recovered in high purity, the latter after applying a solvent extraction scheme based on ethyl acetate, whereby the recoveries of 3-HBA and IL reached approximate to 90%. The compositions of the synthesized ILs and the progress of the hydrolysis process, as well as the purity of the recovered product, were confirmed by NMR analysis. This sustainable approach to selective hydrolytic transformation of PHB into 3-HBA using a recoverable acidic IL catalyst in a biphasic solvent media of aqueous methyl isobutyl ketone hence resulted in efficient product separation and catalyst recovery.