Alternative Feedstock Research Articles

Inverse Vulcanization of Activated Norbornenyl Esters-A Versatile Platform for Functional Sulfur Polymers.

Elemental sulfur has shown to be a promising alternative feedstock for development of novel polymeric materials with high sulfur content. However, the utilization of inverse vulcanized polymers is restricted by the limitation of functional comonomers suitable for an inverse vulcanization. Control over properties and structure of inverse vulcanized polymers still poses a challenge to current research due to the dynamic nature of sulfur-sulfur bonds and high temperature of inverse vulcanization reactions. In here, we report for the first time the inverse vulcanization of norbornenyl pentafluorophenyl ester (NB-PFPE), allowing for post-modification of inverse vulcanized polymers via amidation of reactive PFP esters to yield high sulfur content polymers under mild conditions. Amidation of the precursor material with three functional primary amines (α-amino-ω-methoxy polyethylene glycol, aminopropyl trimethoxy silane, allylamine) was investigated. The resulting materials were applicable as sulfur containing poly(ethylene glycol) nanoparticles in aqueous environment. Cross-linked mercury adsorbents, sulfur surface coatings, and high-sulfur content networks with predictable thermal properties were achievable using aminopropyl trimethoxy silane and allylamine for post-polymerization modification, respectively. With the broad range of different amines available and applicable for post-polymerization modification, the versatility of poly(sulfur-random-NB-PFPE) as a platform precursor polymer for novel specialized sulfur containing materials was showcased.

Enhancing Lettuce Yield through Innovative Foliar Spray of Biopolymers Derived from Municipal Biowastes.

Municipal waste biomass could be valorized as an alternative feedstock to produce compounds beneficial for agricultural applications. The foliar spray application of biostimulants emerges as a promising and innovative technique due to its environmental safety and ability to enhance crop yields. In recent years, the exploitation of biopolymers obtained through alkaline hydrolysis of the solid anaerobic digestate from municipal biowastes has attracted researchers' interest. The aim of this study is to investigate the effects on lettuce growth of a product obtained through alkaline hydrolysis from municipal biowaste, Biopolymers (BPs), and of a derivate subjected to a further oxidation process, Biopolymers Oxidate (BPs OX). The effects of the treatments at various concentrations were evaluated by monitoring plant growth and observing the trends in the activities of the main enzymes involved in the nitrogen metabolic pathway of lettuce. Results suggest that the best treatments in terms of fresh weight were achieved by using BPs at 10 mg/L and BPs OX at 100 mg/L, increasing yield by around 28% and 34%, respectively. The innovative aspect of this work was to make easier for farmers the biopolymers application by testing a foliar spray methodology for BPs and BPs OX, which has never been tested before in any crop.

Toward an Environmentally Friendly Future: An Overview of Biofuels from Corn and Potential Alternatives in Hemp and Cucurbits

Increased energy consumption and climate change, driven by greenhouse gas emissions, pose significant risks to global sustainability. Concerns about using agricultural land for fuel production and its competition with food production have made feedstocks like corn (Zea mays) highly controversial. This study explores the potential of alternative feedstocks, such as hemp (Cannabis sativa) and cucurbits (family Cucurbitaceae), for biofuel production amidst environmental concerns linked to fossil fuel usage. Hemp is widely acknowledged as a promising feedstock for sustainable biorefinery due to its agricultural adaptability and its ability to produce oil and carbohydrates. Cucurbits seeds are characterized by a high oil content, which can be utilized in the food industry or for energy production as biofuel. As a byproduct of cucurbits processing, a significant number of seeds often remains, which constitutes waste. By examining hemp and cucurbit byproducts and waste, which are suitable for bioenergy production, this research highlights the promise these alternative feedstocks hold for the biofuel industry. Utilizing these resources presents a viable route to diminish dependence on fossil fuels and transition toward a more environmentally sustainable energy future.

A synergistic catalytic system of keratinases and disulfide reductases for the bioconversion of feather wastes to feed alternative protein

Effective hydrolysis of feather waste by keratinase is an important way to develop high-quality alternative proteins for feed. It has been shown that the reduction of disulfide bonds is the key rate-limiting step in the hydrolysis of feathers by keratinases. However, the reductive activity of keratinase itself is low. In order to increase the reductive activity of the catalytic system, we screened endogenous disulfide reductase from Bacillus subtilis and constructed a synergistic catalytic system, KerZ1/yjbI-S2-P1, consisting of keratinase and disulfide reductase by co-expression optimization. The reductive activity and feather hydrolytic activity of the synergistic system were 5.67-fold and 5-fold higher than the original system. Feathers were hydrolyzed to a higher extent compared with the original system. The total amino acid and soluble protein concentrations in the products increased by 99% and 59%, respectively. This study provides a more environmentally friendly and efficient reduction capability for keratinase to hydrolysis waste feathers, and also demonstrates a new way of alternative protein feedstock mining.

Novel Catalytic Strategies for the Synthesis of Furans and Their Derivatives

The depletion of fossil resources and their environmental issues make the transition toward alternative feedstock even more urgent [...]

Investigating the barriers and mitigation strategies for biogas adoption in a developing economy: A multi-stakeholder networks perspective

Biogas production is one of the sustainable solutions for tackling organic waste and addressing serious environmental issues. In developing nations, however, stakeholders such as farmers, biogas plant owners, project developers, and investors continue to face diverse challenges in biogas production. Research on potential mitigation strategies to address the complex challenges in biogas adoption in the developing countries context is also scarce. Accordingly, we adopted a multi-stakeholder networks perspective to investigate the barriers and potential strategies for biogas adoption in Pakistan. To this end, we conducted twelve semi-structured interviews with energy consultants and environmental experts working in the biogas industry. Building on the multi-stakeholder networks perspective, the findings contribute to the existing literature by critically analyzing diverse barriers such as the interference of farmer unions, fear of project failure, mindset issues of stakeholders, dependence on a few feedstock suppliers, and lack of policy safeguards for investors. Further, the findings provide in-depth insights into mitigation strategies such as engagement with local communities, proactive biogas policies and best practices in developed and developing economies, cost-benefit analysis of biogas production, close monitoring of the upstream supply chain activities in the biogas industry, incentivizing the segregation of municipal solid waste, and collaboration between industry and academia, which are lacking in the current literature. We argue that rich insights from the present study could facilitate practitioners, stakeholders, and policymakers in advancing sustainable biogas policies and regulatory frameworks, promoting alternative feedstock options, improving stakeholder collaboration, initiating biogas awareness programs, and effectively managing biogas supply chain operations.

The role of Zinc Molybdate in the anticorrosion and antibacterial characteristics of sustainable polyurethane coating derived from epoxidized soybean oil

Vegetable oils are important renewable sources that have been used as alternative feedstocks to petroleum for the synthesis of polyols. Polyols are compounds that contain multiple hydroxyl groups in a molecule and are a major component of polyurethanes. One of the oldest problems that many industries face today is corrosion. Polyurethane coatings reduce the rate of corrosion reactions but are not completely impermeable to corrosive agents. Nanoparticles, due to their high surface area and small particle size, can improve the performance of polyurethane coatings and block the penetration of corrosive agents. This research aims to prepare polyurethane coatings using soybean oil-based polyol and investigate the corrosion resistance performance of polyurethane coatings by adding Zinc Molybdate (ZnMoO4) nanoparticles. To achieve this goal, a polyol based on soybean oil was synthesized through the ring-opening reaction of Epoxidized soybean oil. Then, polyurethane coatings with 0.5, 1, 1.5, and 2 wt% of ZnMoO4 nanoparticles were prepared. Characterization of the polyurethane coatings was performed using FTIR, HNMR, and FESEM. The mechanical properties were also examined. Finally, the corrosion resistance activity of these nanocomposites was evaluated using electrochemical impedance spectroscopy and potentiodynamic polarization tests. The results showed that adding 0.5%w/w of ZnMoO4 nanoparticles can improve the performance of polyurethane coatings against corrosion, as the nanoparticles were uniformly dispersed on the surface of the coating and blocked the penetration of corrosive agents. Therefore, 0.5 wt% ZnMoO4 nanoparticles can be considered as the optimal amount in this experiment. Moreover, the modified coating with ZnMoO4 nanoparticles can effectively act against both gram (+) and gram (-) bacteria.

Evaluation of the potential of activated sludge biomass from Nigeria as a feedstock for biodiesel production

AbstractDepleting fossil fuel reserves and the effects of greenhouse gases on climate change have led to the investigation of alternative energy sources such as biofuel, including biodiesel and renewable diesel. Unfortunately, the cost of the feedstock exceeds 70% of the total production cost. The current work investigates the potential of utilizing a waste product (activated sludge biomass) from wastewater treatment, as an alternative feedstock for biodiesel production. The activated sludge biomass was pretreated with subcritical water to enhance the lipid yield before extracting the lipid using solvent extraction. The result showed that lipid yield from the activated sludge was 4.73–8.58%. After subcritical water pretreatment with varying residence time, temperature, and biomass loading, the lipid yield increased by 158.04–400%. Gas chromatography–mass spectrometry (GC–MS) analysis of the fatty acid methyl esters (FAME) from the transesterification of the lipid extract using calcined egg shell as a catalyst identified the following lipids: triglyceride, fatty acids, sphingolipid, phospholipid, glycerolipid, glycerophospholipid, steroid, and cholesterol. The predominant lipid was triglyceride, and the high percentage of unsaturated fatty acids, including arachidonic acid (23.54%), eicosadienoic acid (8.37%), and oleic acid (6.23%) suggest that the lipid extract is a potential feedstock for biodiesel production.

Conversion of beechwood organosolv lignin via fast pyrolysis and in situ catalytic upgrading towards aromatic and phenolic-rich bio-oil

Lignin, an abundant renewable biopolymer found in plant cell walls, is enriched in phenolic units within its complex molecular structure. Unlocking its potential as alternative feedstock in (bio)refining has posed a long-standing challenge, even though it holds immense promise for replacing fossil-derived phenolic and aromatic compounds. This study focuses on fast pyrolysis as effective thermochemical depolymerization method of lignin, coupled with the in situ catalytic upgrading aiming to produce valuable bio-oil enriched in dealkoxylated (alkyl)phenolic and aromatic compounds. Lignin was isolated via the organosolv process from beechwood sawdust (hardwood biomass). Various acidic aluminosilicate catalysts (e.g., zeolites, such as ZSM-5, Beta and USY, and amorphous silica alumina) were applied, having different Si/Al ratio, porous and acidic properties. Fast pyrolysis experiments were conducted on a fixed-bed bench-scale reactor at two distinct temperatures (500 and 600 °C), employing different contact times and lignin-to-catalyst ratios. Non-catalytic pyrolysis experiments revealed that higher temperature, significantly influences bio-oil’s composition and yield, resulting in the conversion of initially formed alkoxy-phenols to alkyl-phenolic compounds, reaching a 47% relative concentration at 600 °C, while also yielding high amount of bio-oil up to 43 wt%. Among the catalysts tested, zeolite ZSM-5 (Si/Al=40) proved to be the most efficient, shifting the chemical profile of bio-oil from phenolic to aromatic (mainly BTX) with relative concentration of 57%, owing to its unique microporous structure and acidity. Depending on the catalyst type, a balance between BTX monomer aromatics and naphthalenes was observed. Lignin, as well as the obtained products (bio-oil, non-condensable gases, char/coke-on-catalyst) were thoroughly characterized using various analytical techniques. The catalytic upgrading results were associated with the physicochemical properties of the catalysts, providing valuable insights into the underlying reaction mechanisms.

On the intrinsic recycling potential of carbon-based materials and products; an assessment method and outlook

In this paper we investigate the market size of all materials and products presently produced from (organic) carbon and we present a method to estimate the intrinsic recycling potential of these materials/chemicals as a function of their respective applications. The method is based on the expert assessment of a number of variables that are important within the different application categories and markets of the carbon-based materials/chemicals. Applying the method, the paper presents the recycling potential of all carbon-based products. Following, an estimation of the amount of new products that can be produced each year through recycling of discarded products is presented and the amount of carbon that needs to come from other sustainable sources to fulfil our demand for new products is calculated.We distinguish nine different categories of (organic) carbon-based materials/chemicals: plastics, textile fibres, thermoset resins, rubbers, surfactants, solvents, fine chemicals, paper/board and wood products. Within these nine categories the most important materials/chemicals types were taken into account. Fossil-based and bio-based materials/chemicals were assessed separately. For each of the materials/chemicals types, the market size in terms of mass (Mt) was calculated for the main applications in which they are applied. Next, for all materials/chemicals types in these applications, the maximum recycling potential, in case mechanical or physical recycling methods are applied, was assessed, using an expert panel. Also, inevitable leakage of materials/chemicals in the different applications was assessed. Finally, the amount of feedstock coming from recycling streams that may be made available for chemical recycling or carbon capture and utilisation technologies was derived. From this, the magnitude of carbon-based materials/chemicals that need to be replaced each year by other renewable feedstock than recycled content in terms of Mton carbon was calculated.The analysis is relevant in view of implementation of a circular economy and reuse and recycling of materials, to combat depletion of raw materials. Next, it is relevant in view of phasing out fossil-feedstock to combat climate change. Our analysis indicates that the recycling potential of carbon-based materials and products through mechanical or physical methods lies around 50%, even in a system that is fully optimised for recycling. Chemical recycling and carbon capture and utilisation may provide another 25% of the renewable-carbon feedstock needed, but they generally require far more energy and other inputs to produce new materials and chemicals than the mechanical and physical recycling methods. The remaining demand for renewable-carbon feedstock thus needs to come from either biomass or CO2 through carbon capture and utilisation technologies. Based on our findings, we argue that the composition of our present carbon-based products pool needs to be redesigned on a fundamental molecular level, towards material types that contain more oxygen. Carbon-based materials that contain more oxygen generally can be recycled more efficiently, and are also easier to produce from the alternative feedstocks biomass and CO2 through CCU.

Biodiesel production from the microalgae Nannochloropsis gaditana: Optimization of the transesterification reaction and physicochemical characterization

The current environmental scenario has encouraged the study of renewable and competitive alternative feedstocks for biodiesel production. Microalgae present a significant opportunity as a feedstock that does not require arable land and can be cultivated using wastewater. The paper investigates the optimization of biodiesel production from microalgae Nannochloropsis gaditana bio-oil using response surface methodology and also analyzes the main physicochemical properties of the bio-oil. It was confirmed that this methodology is suitable for materials with low homogeneity. The model is also adequate for determining optimal experimental conditions, resulting in a FAME content of 87.25 %. The biodiesel's physicochemical properties were analyzed. It was discovered that the high degree of unsaturation in the microalgae bio-oil's chemical structure resulted in a narrower temperature range for its application compared to other vegetable sources.

Biotechnological Biosuccinic acid (Bio-SA) production from green microalgae Chlorella sp. hydrolysate: Synergistic effect of agitation and substrate concentration assessment using RSM

This paper evaluates the potential of Chlorella sp. microalgae biomass as a feedstock for biosuccinic acid (bio-SA) production via the fermentation process. In this study, the biomass was pretreated and hydrolyzed using a mild acid before being fermented with Actinobacillus succinogenes. The influence of the initial biomass concentration and agitation rate on bio-SA production during batch fermentation was evaluated using a Response Surface Methodology (RSM) design. The results of the study indicated that Chlorella sp. microalgae biomass contained various types of sugars, with glucose identified as the dominant reducing sugar in the Chlorella sp. hydrolysate. According to the RSM analysis, the study showed that changes in the initial biomass concentration and agitation rate could significantly affect bio-SA production from Chlorella sp. hydrolysate. The highest bio-SA concentration of 14.56 g/L with a yield of 0.62 g/g was achieved when fermentation was performed using 10% (w/v) biomass at 150 rpm. Therefore, this study suggests that Chlorella sp. hydrolysate can be an alternative and renewable feedstock for efficient bio-SA production.

An Overview of Microwave Assisted Pyrolysis for Waste Management, with Some Thoughts about Processing Industrial Hemp and Other Woody Wastes

The generation of waste is significantly influenced by the increase in population and industrialization, thereby compelling the increased demand for waste management and resource recovery. This paper investigates the potential opportunities presented by the utilization of microwave-assisted pyrolysis for processing plastic and organic waste materials, with a particular focus on industrial hemp leaves, hurds, and root materials, and other feedstocks. Drawing from a range of published studies, it is suggested that microwave-assisted pyrolysis has the potential to achieve energy neutrality or even energy generation, if all byproducts are used. Depending on factors such as recoverable volumes and the associated recovery costs of commercially significant chemicals like vinegars and bio-oils, the microwave-assisted pyrolysis of industrial hemp leaves, hurds, and root materials may prove to provide high return of the yield and profits. Additionally, this paper explores the production of other valuable byproducts such as syngas and biochar from alternative feedstocks, particularly when data related to hemp processing is not readily available.

Exploring the phytochemical, antioxidant, antimicrobial and analgesic potentials of Solanum erianthum as an alternative biological feedstock for producing sustainable biochemicals

Solanum erianthum is a medicinal herb that offers health benefits and valuable phytochemicals in treating human ailments. Phytochemicals and therapeutic properties of different parts of S. erianthum in four solvents: water, petroleum ether, chloroform, and methanol were evaluated. Stem showed high alkaloids (15.40 ± 0.7%) and tannins (8.6 ± 0.3%), followed by higher root saponins (12.2 ± 0.2%). In contrast, leaf exhibited high flavonoid (13.5 ± 0.5%) and phenolic (12.30 ± 1.0%) contents. The petroleum ether extract of the stem had the highest 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging activity (70.66 ± 0.3%) and ferric reducing antioxidant power (FRAP) activity (70.55 ± 0.08 μg/mL). In contrast, the petroleum ether extract of the root had maximum total antioxidant capacity (TAC) (1.065 ± 0.6 absorbance at 695 nm), while the fruit aqueous extract showed highest activity in ferric thiocyanate assay (FTC) (61.53 ± 0.1). Antibacterial activity ranged from 19 to 51 mm, while antifungal was from 11 to 43 mm. The methanol extracts of the root and leaf showed the highest antimicrobial activity against the tested bacteria and fungi. The methanol extract of fruit showed the highest analgesic activity (11.98 ± 2.14 s) and writhing inhibition (1st phase 85.1% and 2nd phase 96.7%), as confirmed by the formalin-induced paw licking test. Fruit extract showed active central and peripheral analgesic effects in early (88.9%) and late (92.8%) phases of pain, comparable to paracetamol (60 mg/kg). In conclusion, this study demonstrates the antioxidant, antimicrobial, and antifungal properties as well as central and peripheral analgesic effects of S. erianthum extracts.

Toward Circular Economy: Potentials of Spent Coffee Grounds in Bioproducts and Chemical Production

With growing concern over environmental sustainability and dwindling fossil resources, it is crucial to prioritise the development of alternative feedstocks to replace fossil resources. Spent coffee grounds (SCGs) are an environmental burden with an estimated six million tons being generated on a wet basis annually, globally. SCGs are rich in cellulose, lignin, protein, lipids, polyphenols and other bioactive compounds which are important raw materials for use in industries including pharmaceuticals and cosmetics. Furthermore, the energy sector has the potential to capitalize on the high calorific value of SCGs for biofuel and biogas production, offering a sustainable alternative to fossil fuels. SCGs are readily available, abundant, and cheap, however, SCGs are currently underutilized, and a significant amount are dumped into landfills. This review explores the potential of SCGs as a source of a value-added compound through various conversion technologies employed in the valorisation of SCGs into biochar, biofuel, and important chemical building blocks. The state-of-the-art, current knowledge, future research to stimulate the creation of sustainable products, and the challenges and economic feasibility of exploring SCGs in a biorefinery context are presented.

A sustainable synthesis of polyhydroxyalkanoate from stubble waste as a carbon source using Pseudomonas putida MTCC 2475.

Polyhydroxyalkanoates (PHAs) are biodegradable polymers that can be produced from lignocellulosic biomass by microorganisms. Cheap and readily available raw material, such as corn stover waste, has the potential to lessen the cost of PHA synthesis. In this research study, corn stover is pretreated with NaOH under conditions optimized for high cellulose and low lignin with central composite design (CCD) followed by characterization using Fourier-transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM). Design expert software performed further optimization of alkali pretreated corn stover for high total reducing sugar (TRS) enhancement using CCD using response surface methodology (RSM). The optimized condition by RSM produced a TRS yield of 707.19mg/g. Fermentation using corn stover hydrolysate by Pseudomonas putida MTCC 2475 gave mcl-PHA detected through gas c hromatography - t andem m ass s pectrometry (GC-MS/MS) and characterization of the PHA film by differential scanning calorimetry (DSC), FTIR, and nuclear magnetic resonance (NMR). Thus, this research paper focuses on using agriculture (stubble) waste as an alternative feedstock for PHA production.

Impact of irradiance and inorganic carbon availability on heterologous sucrose production in Synechococcus elongatus PCC 7942.

Cyanobacteria have been proposed as a potential alternative carbohydrate feedstock and multiple species have been successfully engineered to secrete fermentable sugars. To date, the most productive cyanobacterial strains are those designed to secrete sucrose, yet there exist considerable differences in reported productivities across different model species and laboratories. In this study, we investigate how cultivation conditions (specifically, irradiance, CO2, and cultivator type) affect the productivity of sucrose-secreting Synechococcus elongatus PCC 7942. We find that S. elongatus produces the highest sucrose yield in irradiances far greater than what is often experimentally utilized, and that high light intensities are tolerated by S. elongatus, especially under higher density cultivation where turbidity may attenuate the effective light experienced in the culture. By increasing light and inorganic carbon availability, S. elongatus cscB/sps produced a total of 3.8 g L-1 of sucrose and the highest productivity within that period being 47.8 mg L-1 h-1. This study provides quantitative description of the impact of culture conditions on cyanobacteria-derived sucrose that may assist to standardize cross-laboratory comparisons and demonstrates a significant capacity to improve productivity via optimizing cultivation conditions.

A Comprehensive exploration of jatropha curcas biodiesel production as a viable alternative feedstock in the fuel industry – Performance evaluation and feasibility analysis

Jatropha Curcas stands out as a promising plant-based feedstock, offering a non-edible oil that holds great potential as an alternative fuel to traditional diesel. Notably, Jatropha oil boasts favourable fuel properties, including a higher oil content compared to other alternatives. This attribute makes it an attractive candidate for biodiesel production. Importantly, as a non-edible oilseed feedstock, Jatropha Curcas helps mitigate concerns related to food prices and the ongoing food versus fuel debate, offering a sustainable solution to the growing energy demands. Furthermore, the plant exhibits impressive yields, with the potential to produce up to 40% oil weight per seed. This high yield not only enhances the economic viability of Jatropha-based biodiesel but also underscores its efficiency as a feedstock. The discussion extends beyond mere fuel properties, encompassing a comprehensive comparative review that delves into engine performance and emission characteristics associated with Jatropha Curcas. The novelty of this paper lies in its exploration of the crude oil aspects of Jatropha curcas, shedding light on an essential facet often overlooked. By presenting a thorough analysis of fuel properties, engine performance, and emission characteristics, the paper contributes valuable insights to the discourse on sustainable energy solutions. Moreover, it goes beyond technical aspects and provides perspectives on the current economic status, offering a holistic view of the potential impact of Jatropha Curcas in the broader context of renewable energy and economic development.

Microalgal biochar assisted simultaneous removal of particulate matter, formaldehyde, and total volatile organic compounds (TVOC's) from indoor air

Biochar-based materials for air treatment have gained significant attention for removing health-detrimental volatile organic compounds (VOCs) and particulate matter (PM) in indoor air settings. However, high turnaround time, multiple pretreatment processes involved, and high pore size and low surface area (>10 μm, <100 m2 g−1) of lignocellulosic feedstocks demand alternative biochar feedstock material. Considering this, we designed a simple first-of-its-kind indoor air scrubbing material using diatoms-enriched microalgae biochar. In the present study, the microalgae were cultivated on waste anaerobic digestate (biogas slurry) and were pyrolyzed at three different temperatures: 300 °C (BC300), 500 °C (BC500), and 700 °C (BC700). The BC500 and BC700 showed the highest removal efficiencies (99 %) for total volatile organic carbons (TVOCs) and formaldehyde (HCHO) at concentrations of 1.22 mg m−3 HCHO and 8.57 mg m−3 TVOC compared to 50% efficiency obtained with commercially available surgical, cloth, and N95 masks. The biochar obtained showed a high Brunauer–Emmett–Teller (BET) surface area of 238 m2 g−1 (BC500) and 480 m2 g−1 (BC700) and an average pore size of 9–11 nm due to the mesoporous characteristic of diatom frustules. The comparatively poor performance of BC300 was due to lower surface area (150 m2 g−1) arising from incomplete organic removal, as evidenced by FESEM-EDX and FTIR. The high removal efficiencies in BC500 and BC700 were also attributed to the presence of reactive functional groups such as –OH and R–NH2. Concurrently, the average particulate matter (PM10, PM2.5, and PM1) removal efficiency for BC500 and BC 700 ranged between 66 and 82.69 %. The PM removal performance of BC500 and BC700 was lower (15–20%) than commercially available masks. Overall, the present study highlights the importance of diatoms (reactive Si) present inside the pores of microalgal biochar for enhanced removal of PM, TVOCs, and HCHO at temperatures above 500 °C. This complete approach signifies a step towards establishing a self-sustainable and circular process characterized by minimal waste generation for indoor air treatment.

Sugar content improvement by sonication in the pretreatment of empty fruit bunch hydrolysis

The empty palm fruit bunches (EFB) has great potential as an alternative feedstock for bioethanol production due to its high content of cellulose and hemicellulose. However, besides cellulose and hemicellulose, EFB also contains lignin, which can hinder the hydrolysis process and therefore requires delignification. This study aims to determine the effect of sonication in alkali delignification on the sugar content of hydrolysis. Ultrasonic in 37 KHz was performed at a temperature of 80 °C. Sonication process durations ranged from 30 minutes to 150 minutes using a 10 % (w/v) NaOH solvent. The hydrolysis of EFB fibers was carried out in a water bath at 80 °C using a 0.5 N sulfuric acid solvent in a ratio of 1:20 (w/v) for 2 hours. The sugar content was measured using the phenol-sulfuric acid method with UV-Visible spectrophotometry. In this study found that the ultrasonic irradiation time length gave good results at a time limit not exceeding 90 minutes due to hemicellulose characteristics . The highest sugar content was obtained at a sonication duration of 90 minutes, measuring 20.60 mg/L, which was 38.5 % higher than alkali delignification without sonication for 150 minutes. SEM analysis indicated that EFB had undergone changes in the surface morphology and structure. Qualitative FTIR analysis showed that the hydrolysis solution contained glucose and pentose, which are products of hydrolyzed cellulose and hemicellulose.