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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.

This research explores the potential of abundant biopolymers, specifically chitin and lignin, found in biomass byproducts to address environmental and energy challenges.

Chitin, commonly found in crustacean shells, can be deacetylated to produce chitosan, a versatile material with various industrial applications. Traditional chitosan production is energy-intensive and uses corrosive reagents.  In order to improve the process, Paper I introduces a ‘greener’ method, using the ionic liquid [Emim][OAc] for chitin pretreatment, followed by microwave-assisted deacetylation in aqueous NaOH or [TBA][OH] solutions. The pretreatment effectively reduces the chitin crystallinity, improving its reactivity for achieving up to 85% deacetylation in 1-2 hours. Both [Emim][OAc] and [TBA][OH] are regenerated (97% and 83%, respectively), offering a more sustainable chitosan production method, which can serve as a substrate for e.g. catalysts in industry. Paper II investigates the adsorption and catalytic reduction of phenol red dye using Ag-loaded chitosan catalysts. These catalysts display excellent activity across a broad pH range (4–11), with efficient adsorption at near-neutral pH (6.4) and room temperature. After five recycling cycles, the catalysts maintain structural stability, with only a 0.2% loss of Ag, demonstrating their potential for wastewater treatment.

Lignin, an abundant but underutilized polymer in wood biomass, is typically burned for heat. Recent interest has focused on converting lignin into valuable products like jet-fuel range hydrocarbons and fine chemicals. The challenge is selectively breaking C–O and C–C bonds in lignin while maintaining catalyst stability. Paper III explores C–O cleavage in lignin models using multifunctional Ru/NbOPO₄/TiO₂ catalysts, achieving high yields of hydrocarbons (86.9–100%) under mild conditions. Paper IV investigates both C–O and C–C cleavage with Ru/NbOPO₄ catalysts, producing >99% conversion in model compounds with high yield of hydrocarbons. The catalysts’ performance is driven by the tunable synergy between Lewis and Brønsted acid sites of niobium phosphate and the hydrogen activation role of Ru.

This interdisciplinary research advances biopolymer chemistry and catalysis, offering sustainable solutions for environmental and energy challenges by maximizing biomass byproducts and providing eco-friendly alternatives in wastewater treatment and renewable energy.

Denna forskning undersöker potentialen hos två viktiga biopolymerer, specifikt kitin och lignin, som finns i biprodukter från biomassa, för att möta miljö- och energirelaterade utmaningar. 

Kitin, som vanligen återfinns i kräftdjurskal, kan deacetylseras för att producera kitosan, ett mångsidigt material med olika industriella tillämpningar. Traditionell kitosanproduktion är energikrävande och använder korrosiva reagenser. För att förbättra denna process introducerar Paper I en ’grönare’ metod, där den joniska vätskan [Emim][OAc] används för förbehandling av kitin, följt av mikrovågshjälpt deacetylation i vattenlösningar av NaOH eller [TBA][OH]. Förbehandlingen reducerar effektivt kitinets kristallinitet och förbättrar dess reaktivitet för att uppnå upp till 85% deacetylation på 1-2 timmar. Både [Emim][OAc] och [TBA][OH] kan regenereras (97% respektive 83%), vilket erbjuder en mer hållbar metod för kitosanproduktion som kan tex. fungera som substrat för katalysatorer i industrin. Paper II undersöker adsorption och katalytisk reduktion av fenolröd färgämne med Ag-belastade kitosankatalysatorer. Dessa katalysatorer visar utmärkt aktivitet över ett brett pH-intervall (4–11), med effektiv adsorption vid nästan neutralt pH (6,4) samt vid rumstemperatur. Efter fem återvinningscykler bibehåller katalysatorerna deras strukturella stabilitet med endast 0,2% förlust av Ag, vilket visar deras potential för avloppsvattenrening.

Lignin, en viktig men underutnyttjad polymer i träbiomassa, bränns vanligtvis till energi och värme. Nyligen har intresset ökat för att omvandla lignin till värdefulla produkter som jetbränsle-kolväten och finkemikalier. Utmaningen ligger i att selektivt bryta C–O och C–C-bindningar i lignin samtidigt som katalysatorns stabilitet bibehålls. Paper III undersöker C–O-klyvning i ligninmodelmolekyler med multifunktionella Ru/NbOPO₄/TiO₂-katalysatorer, vilket ger hög utbyte av kolväten (86,9–100%) under milda betingelser. Paper IV undersöker både C–O och C–C-klyvning med Ru/NbOPO₄-katalysatorer, varvid >99% konversion av modellföreningar uppnås med högt utbyte av kolväten. Katalysatorernas prestanda drivs av den justerbara synergismen mellan Lewis- och Brønsted-surheten hos niobiumfosfat och väteaktiveringsrollen hos Ru.

Denna tvärvetenskapliga forskning främjar biopolymerkemi och katalys, och erbjuder hållbara lösningar till miljö- och energimässiga utmaningar genom att maximera användningen av biprodukter från biomassa och tillhandahålla miljövänliga alternativ inom avloppsvattenrening och förnybar energi.

Nghiên cứu này nhằm khám phá tiềm năng của những polymer sinh học có trong các phụ phẩm sinh khối, cụ thể là chitin và lignin, trong việc giải quyết các thách thức về môi trường và năng lượng.

Chitin được tìm thấy nhiều trong vỏ động vật giáp xác và có thể deacetyl hóa để tạo ra chitosan, một vật liệu đa dụng với nhiều ứng dụng trong công nghiệp. Sản xuất chitosan truyền thống thường tiêu tốn nhiều năng lượng và cần đến các tác chất có tính ăn mòn cao. Để cải thiện, Bài báo I giới thiệu một phương pháp ’xanh hơn’, sử dụng chất lỏng ion [Emim][OAc] để xử lý sơ bộ chitin, sau đó tiến hành deacetyl hóa trong dung dịch NaOH hoặc [TBA][OH] với sự hỗ trợ của vi sóng. Quá trình tiền xử lý giúp giảm độ tinh thể của chitin, tăng hoạt tính phản ứng, và đạt tới 85% deacetyl hóa trong 1-2 giờ. Cả [Emim][OAc] và [TBA][OH] đều có thể tái tạo với hiệu suất tương ứng 97% và 83%, đem lại tính bền vững cho phương pháp, và tăng thêm cơ hội cho chitosan trong các ngành công nghiệp, thí dụ như xúc tác. Bài báo II nghiên cứu quá trình hấp phụ và khử thuốc nhuộm phenol đỏ bằng xúc tác Ag/chitosan. Xúc tác này thể hiện hoạt tính cao với phạm vi pH rộng (4–11), và khả năng hấp phụ hiệu quả nhất ở pH gần trung tính (6.4), nhiệt độ phòng. Sau năm lần tái sử dụng, xúc tác vẫn duy trì độ ổn định cấu trúc, mất chỉ 0.2% Ag, chứng minh tiềm năng trong xử lý nước thải.

Lignin là một polymer phổ biến trong sinh khối gỗ, nhưng chưa được khai thác nhiều, mà thường chỉ bị đốt để tạo nhiệt năng. Gần đây, nhiều nghiên cứu bắt đầu tập trung vào việc chuyển hóa lignin thành các sản phẩm có giá trị hơn, như phụ gia nhiên liệu máy bay hay hóa chất thương phẩm. Thách thức nằm ở việc bẻ gãy chọn lọc các liên kết C–O và C–C trong lignin đồng thời duy trì khả năng tái sử dụng của xúc tác. Bài báo III nghiên cứu sự cắt đứt C–O trong các hợp chất mô phỏng lignin bằng xúc tác đa năng Ru/NbOPO₄/TiO₂. Nghiên cứu cho hiệu suất chuyển hóa cao (86.9–100%), sản xuất hydrocarbon trong điều kiện êm dịu hơn. Bài báo IV nghiên cứu việc cắt đứt đồng thời C–O và C–C với xúc tác Ru/NbOPO₄ trong các hợp chất mô phỏng lignin. Chuyển hóa thu được hơn 99% với hiệu suất hydrocarbon cao. Hiệu quả của các xúc tác này liên quan đến sự kết hợp giữa các tâm acid Lewis và Brønsted trong niobium phosphate và sự hoạt hóa hydrogen của Ru.

Nghiên cứu này làm màu mỡ thêm hóa học về polymer và xúc tác, cung cấp thêm các giải pháp bền vững cho các thách thức về môi trường và năng lượng thông qua việc tối đa hóa các phụ phẩm sinh khối trong xử lý nước thải và năng lượng tái tạo.

Hardwood spent mushroom substrate was employed as a carbon precursor to prepare activated biochars using phosphoric acid (H3PO4) as chemical activator. The activation process was carried out using an impregnation ratio of 1 precursor:2 H3PO4; pyrolysis temperatures of 700, 800, and 900 °C; heating rate of 10 °C min−1; and treatment time of 1 h. The specific surface area (SSA) of the biochars reached 975, 1031, and 1215 m2 g−1 for the samples pyrolyzed at 700, 800, and 900 °C, respectively. The percentage of mesopores in their structures was 75.4%, 78.5%, and 82.3% for the samples pyrolyzed at 700, 800, and 900 °C, respectively. Chemical characterization of the biochars indicated disordered carbon structures with the presence of oxygen and phosphorous functional groups on their surfaces. The biochars were successfully tested to adsorb acetaminophen and treat two simulated pharmaceutical effluents composed of organic and inorganic compounds. The kinetic data from adsorption of acetaminophen were fitted to the Avrami fractional-order model, and the equilibrium data was well represented by the Liu isotherm model, attaining a maximum adsorption capacity of 236.8 mg g−1 for the biochar produced at 900 °C. The adsorption process suggests that the pore-filling mechanism mainly dominates the acetaminophen removal, although van der Walls forces are also involved. The biochar produced at 900 °C removed up to 84.7% of the contaminants in the simulated effluents. Regeneration tests using 0.1 M NaOH + 20% EtOH as eluent showed that the biochars could be reused; however, the adsorption capacity was reduced by approximately 50% after three adsorption–desorption cycles.

A highly efficient method for the direct construction of amide bonds via a selective cleavage of C-H and C=C bonds in indole structures using an iodine-promoted approach was developed. Mechanistic studies indicated the formation of superoxide radicals obtained from molecular oxygen activation as a key intermediate step, which provided a precursor for subsequent oxidative ring-opening and intermolecular cyclization. A broad range of quinazolin-4(3H)-ones and tryptanthrins were synthesized in moderate to good yields under mild and environmentally benign conditions.

To produce chitosan is an interesting research. Chitosan is an important polysaccharide in terms of its various applications in industries and is produced from chitin, an abundant biopolymer in crustacean shell biomass wastes. Traditional processes for chitosan manufacture are commonly based on highly concentrated alkaline or acid solutions which are, however, severely eroding and harmful to the environment. In this study, we have described a ‘greener’ method using 1-ethyl-3-methylimidazolium acetate, [Emim][OAc] ionic liquid (IL), for decrystallization of shrimp crystalline chitin flakes followed by a microwave-mediated NaOH or tetrabutylammonium hydroxide, [TBA][OH], solution-based deacetylation for chitosan production. The decrease in crystallinity in IL pre-treated chitin was confirmed by XRD and SEM analysis which subsequently benefited chitosan production with up to 85% degree of deacetylation (%DDA) in shorter time periods (1-2 hours) and lower alkaline concentrations (20-40%). The %DDA in chitin/chitosan was estimated via FT-IR and NMR analysis. Notably, we could regenerate the ionic liquids: in case of [Emim][OAc] 97 wt.% and in case of [TBA][OH] 83 wt.% could be reused. Roles of ionic liquids in the process were discussed. Molecular dynamics (MD) simulations showed the roles of [TBA]+ cations in the molecular driving forces of [TBA][OH]-induced deacetylation mechanism. The strategy promises a sustainable and milder reaction approach to the existing highly corrosive alkaline- or acid-involved processes for chitosan production.

Cellulose fiber rejects from industrial-scale recycling of waste papers were dried and de-ashed using a combined cyclone-drying and sieving process. The upgraded fiber reject was used as a component of substrates for the cultivation of Pleurotus ostreatus and Pleurotus eryngii mushrooms. Acetic acid (AA) and acid whey (AW) were used to adjust the pH of fiber reject-based substrates. Spent substrate (SMS) was used for the production of activated biochar using H₃PO₄ and KOH as activating agents and pyrolysis temperatures of 500, 600, and 700 °C. The effectiveness of the biochars in removing pollutants from water was determined using acetaminophen and amoxicillin. By using a feeding rate of 250 kg/h and a drying air temperature of 70 °C, the moisture content of the raw fiber rejects (57.8 wt %) was reduced to 5.4 wt %, and the ash content (39.2 wt %) was reduced to 21.5 wt %. Substrates with 60 and 80 wt % de-ashed cellulose fiber were colonized faster than a birch wood-based control substrate. The adjustment of the pH of these two substrates to approximately 6.5 by using AA led to longer colonization times but biological efficiencies (BEs) that were higher or comparable to that of the control substrate. The contents of ash, crude fiber, crude fat, and crude protein of fruit bodies grown on fiber reject-based substrates were comparable to that of those grown on control substrates, and the contents of toxic heavy metals, that is, As, Pb, Cd, and Hg, were well below the up-limit values for food products set in EC regulations. Activated biochar produced from fiber reject-based SMS at a temperature of 700 °C resulted in a surface area (BET) of 396 m²/g (H₃PO₄-activated biochar) and 199 m²/g (KOH-activated biochar). For both activated biochars, the kinetics of adsorption of acetaminophen and amoxicillin were better described using the general order model. The isotherms of adsorption were better described by the Freundlich model (H₃PO₄-activated biochar) and the Langmuir model (KOH-activated biochar).

In this study, glutaraldehyde cross-linked chitosan support, as well as the catalysts obtained after loading Ag metal (Ag/Chitosan), were synthesised and applied for adsorption and reduction of phenol red dye in an aqueous solution. The Ag/chitosan catalysts were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and inductively coupled plasma-optical emission spectrometry (ICP-OES) analysis techniques. The catalytic reduction and adsorption performance of phenol red dye with Ag/chitosan and cross-linked chitosan, respectively, was performed at ambient reaction conditions. The reduction of dye was carried out using sodium borohydride (NaBH4) as the reducing agent, while the progress of adsorption and reduction study was monitored with ultraviolet-visible (UV-vis) spectrophotometry technique. The reduction of the phenol red dye varied with the amount of catalyst, the concentration of NaBH4, Ag metal loading, reaction temperature, phenol red dye concentration and initial pH of the dye solution. The dye solution with a nearly-neutral pH (6.4) allowed efficient adsorption of the dye, while acidic (pH = 4) and alkaline (pH = 8, 11, 13.8) solutions showed incomplete or no adsorption of dye. The reusability of the Ag/chitosan catalyst was applied for the complete reduction of the dye, where no significant loss of catalytic activity was observed. Hence, the applicability of cross-linked chitosan and Ag/catalyst was thus proven for both adsorption and reduction of phenol red dye in an aqueous solution and can be applied for industrial wastewater treatment.

Preparing sustainable and highly efficient biochars as adsorbents remains a challenge for organic pollutant management. Herein, a novel nitrogen-doped carbon material has been synthesized via a facile and sustainable single-step pyrolysis method using a wild mixture of microalgae as novel carbon precursor. Phosphoric acid (H₃PO₄) was employed as activation agent to generate pores in the carbon material. In addition, the effect of melamine (nitrogen source) was evaluated over the biochar properties by the N-doping process. The results showed that the biochar's specific surface area (SSA) increased from 324 to 433 m² g⁻¹ with the N-doping process. The N-doping process increased the percentage of micropores in the biochar structure. Chemical characterization of the biochars indicated that the N-doping process helped to increase the graphitization process of the biochar and the contents of oxygen and nitrogen groups on the carbon surface. The biochars were successfully tested to adsorb acetaminophen and treat two synthetic effluents, and the N-doped biochar presented the highest efficiency. The kinetics and equilibrium data were well represented by the General-order model and the Liu isotherm model, respectively. The maximum sorption capacities attained were 101.4 and 120.7 mg g⁻¹ for the non-doped and doped biochars, respectively. The acetaminophen adsorption mechanism suggests that the pore-filling was the dominant mechanism for acetaminophen uptake. The biochars could efficiently remove up to 74% of the contaminants in synthetic effluents.

In this report, 1-ethyl-3-methylimidazolium acetate, [EMIM][AcO] ionic liquid (IL) and acetic acid (AA) comprised solvents were used for the thermal treatment of poly (vinylidene difluoride), PVDF. Here, besides the various combinations of IL and AA in solvents, the pure IL and AA were also applied as a solvent upon thermal treatments. The samples obtained after the treatment were analysed for structural and crystalline phase changes, porosity, and molecular weight distribution with various analytical techniques. The Kamlet-Taft parameters measurement of the IL and AA containing solvents with different solvatochromic dyes was also performed to examine their solvent properties and correlate with the properties of the treated PVDF materials. The treatment of PVDF with pure IL results in the formation of highly carbonaceous material due to extensive dehydroflurination (DHF) as well as possibly successive cross-linking in the polymer chains. Upon IL and AA combined solvent treatment, the neat PVDF which composed of both α- and β crystalline phases was transformed to porous and β-phase rich material whereas in case of pure AA the non-porous and pure α-phase polymeric entity was obtained. A combined mixture of IL and AA resulted in a limited the DHF process and subsequent cross-linking in the polymer chains of PVDF allowed the formation of a porous material. It was observed that the porosity of the thermally treated materials was steadily decreasing with increase in the amount of AA in solvents composition and solvent with an AA:IL mole ratio of 2:1 resulted in a PVDF material with the highest porosity amongst the applied solvents. A recovery method for the IL and AA combined solvent after the thermal treatment of PVDF was also established. Hence, with varying the type of solvents in terms of composition, the highly carbonaceous materials as well as materials with different porosities as well as crystalline phases can be obtained. Most importantly here, we introduced new IL and AA containing recoverable solvents for the synthesis of porous PVDF material with the electroactive β-phase.

The quest to develop flexible membrane-like supercapacitors to be applied in advanced electronic devices with a flexible structure is important for the modern world. In this study, we developed biomass-based supercapacitors by depositing activated carbon on an eggshell membrane and subsequently coating these with polypyrrole in a two-step procedure. The competition between the electrical double layer capacitance (EDLC) from activated carbon and the pseudocapacitance (PC) for the hybrid device is controlled by varying the amount of polypyrrole (PC component) in a time-dependent polymerization process. An areal capacitance of 172.5 mF cm−2, a corresponding energy density of 4.73 W h kg−1, and power density of 320.8 W kg−1, with a 60% retention even after 1000 cycles were obtained for samples prepared with the polymerization of polypyrrole on the activated carbon (incorporation of an active layer of 3.18 mg cm−2).