Acid Pretreatment Of Biomass Research Articles

Novel strategy to produce polyaromatic compounds at low temperature for the production of secondary chars

The production of polyaromatic compounds during biomass thermochemical processing at temperatures over 700 °C from the secondary reactions pyrolysis vapors is a well study phenomena. These compounds are sometimes used to produce carbonaceous materials (such as carbon black, carbon nanotubes). In the case of gasification these polyaromatic compounds form tars and are a major source of problems for the operation of these reactors. In this paper we explore the use of acid impregnation, particularly using phosphoric acid, to reduce the temperature at which small polyaromatic rings are formed and released from the biomass. The acid treatment of biomass was found to increase the yield of biochar (from 17 wt% to 40 wt%) and to be an excellent source of polyaromatic compounds (close to 15 wt% on biomass dry basis). In this manuscript we explored the use of the small polyaromatic ring systems produced from the carbonization of acid-pretreated biomass as precursors for the synthesis of secondary carbons. A two-step pyrolysis process was conducted on acid-treated biomass, revealing that the volatiles produced in the first stage were primarily derived from the dehydration of anhydrosugars. In contrast, the volatiles produced in the second stage were found to be primarily composed of aromatic compounds similar to those produced in gasification processes, with low to no oxygen content. In this research, we have introduced an innovative strategy to maximize the benefits of acid-treated biomass pyrolysis by utilizing the low oxygen aromatic hydrocarbons compounds produced as a carbon source for the production of carbon nanostructures (CNS) on biochar-supported nickel catalysts. This methodology allows to produce polyaromatic compounds at very low temperature from lignocellulosic materials. This not only optimizes the utilization of biomass resources but also enhances the yield of high-value products and aligns with the principles of a circular economy.

Technoeconomic analysis of broccoli biorefineries for polyphenol extraction and biobutanol production

Fossil resources dominate the energy supply. In 2019, the total energy supply worldwide accounted for 606 exajoules (EJ), of which fossil fuels (oil, coal, and gas) had a share of 81% (490 EJ). The biorefinery concept proposes the synthesis of renewable energies as an alternative to fossil carburants. As a second-generation biofuel, biobutanol has outstanding characteristics and can be obtained from agricultural residues and organic wastes; however, its bioprocessing is not economically feasible using current methodologies. In 2021, the global production of broccoli (Brassica oleracea var. Italica) was 25.5 million tons; being the fifth top producer, Mexico generated 687,000 tons of this vegetable. In this work we propose a production design for the synthesis of biobutanol and the recovery of valuable byproducts, like high-value polyphenolic compounds, from broccoli residues, abundant in the state of Guanajuato, Mexico. For the transformation of the substrate a biochemical matrix was proposed for its composition, as well as a biotechnological route that follows a general path with the acid pretreatment of biomass, enzymatic hydrolysis, and acetone-biobutanol-ethanol (ABE) fermentation using anaerobic bacteria. The outlined biorefinery integrates conventional methods in three methodological pathways and a hybrid model for the downstream process. With the aim of visualizing the global economic performance and evaluating a possible reduction in production costs, we performed a technoeconomic analysis of the designed second generation biorefinery plant. The economic evaluation was carried out using SuperPro Designer® V 12.0. The results confirm the enormous dependence that this type of biorefinery suffers from energy demands. We found that by implementing strategic adaptations to the downstream process operating costs can be considerably reduced. However, to achieve full financial efficiency in the production of biobutanol from broccoli residues, it is necessary to deepen the research and development of innovative methods to efficiently separate and purify the final products, as well as novel methodologies for the biotransformation of the described lignocellulosic biomass along the entire technological route. We also found that there is a large opportunity in the valorization of the plentiful broccoli residues generated in the Guanajuato region.

Enzymatic digestibility of pretreated dewaxed bamboo residues as feedstock for bioethanol production

Due to abundant availability, biofuel production from bamboo residues is gaining popularity. Bamboo biomass and its residues are widely available in the north-eastern part of India, which can be sustainably exploited for green energy production. The aim of the present study was to evaluate the pretreatments of dewaxed bamboo residues with dilute alkali (NaOH), and dilute acid, and the effect of pretreatment on biomass hydrolysis was performed with a commercial enzyme (Zytex). Results showed that maximum fermentable sugars were 490 mg/g obtained from 10% biomass with 0.6% (w/v) of alkali, and acid pretreated biomass produced 320 mg/g of sugars from 2% (w/v) acid with 10% biomass. Changes in biomass structure during the pretreatment process are correlated with FTIR, SEM, and component analysis for lignin, cellulose, and hemicelluloses. Fermentation studies of the hydrolysate showed that the yield of ethanol was 77% of the theoretical maximum at 36 h. Results indicate the scope of utilization of bamboo residues as substrates for biofuels, and alkaline pretreatment is an effective pretreatment process for bioethanol production.

Non-detoxified acid hydrolysate of de-oiled Pongamia seed cake as a low-cost solution to microbial oil synthesis

• A lignocellulose residue, derived as a biodiesel byproduct, was used for microbial oil synthesis. • Acid pretreated biomass was used for lipid fermentation without detoxification. • The biomass and lipids in detoxified and non-detoxified media did not significantly differ. • A. ochraceus was resistant to inhibitors in the non-detoxified medium. • Avoiding the detoxification step may improve process economics. With rising energy demands, alternative transportation fuels are continually sought. The most recent advances in this area have been in the use of microorganisms to produce oils for biodiesel. When pretreated with dilute acid and used for microbial fermentation, the lignocellulosic sources currently preferred for microbial oil production require an additional detoxification step. In this work, microbial oil was produced from de-oiled Pongamia cake, a low-value residue from the biodiesel industry, to evaluate whether the detoxification step might be omitted during raw material processing. Non-detoxified acid hydrolysate (NDAH) and detoxified acid hydrolysate (DAH), when subjected to fermentation with Aspergillus ochraceus , produced comparable biomass and lipid concentrations, with a maximum biomass of 22.249 g/L and 21.445 g/L, and maximum lipid of 4.463 g/L and 4.106 g/L, in NDAH and DAH media, respectively, thus indicating that detoxification might be avoided. Detoxifying the medium decreased the concentrations of the fermentation inhibitors furfural, 5-hydroxymethyl furfural (HMF), and acetic acid; however, the microorganism was resistant to the inhibitors, thus demonstrating that bio-oil can be produced from acid-pretreated Pongamia cake without any detoxification procedure. Overall, these results may enable the elimination of additional process and operating costs.

Investigation of the effects of pretreatment on the elemental composition of ash derived from selected Nigerian lignocellulosic biomass

Lignocellulosic biomass is an important source of renewable energy and a potential replacement for fossil fuels. In this work, the X-ray fluorescence (XRF) method was used to analyze the elemental composition of raw and pretreated lignocellulosic biomass of cassava peels, corn cobs, rice husks, sugarcane bagasse, yam peels, and mixtures of cassava peels and yam peels, corn cobs and rice husks and all five biomass samples combined. The influence of particle size on elemental properties was investigated by screening the selected biomass into two size fractions, of an average of 300 and 435 µm, respectively. The total concentration of Mg, Al, Si, P, S, Cl, Ca, Ti, Cr, Mn, Fe, Co, Cu, Zn, Sn, Ni, Br, Mo, Ba, Hg, and Pb were determined for each of the biomass samples before and after the different pretreatments adopted in this study. From the results of the analysis, there was a significant reduction in the concentration of calcium in all the analyzed biomass after the alkaline pretreatment with rice husks biomass having the lowest concentration of 66 ppm after the alkaline pretreatment. The sulfur content of the acid pretreated biomass increased considerably which is likely due to the sulfuric acid used for the acid pretreatment. The fact that a mixture of biomass feedstock affects the properties of the biomass after pretreatment was validated in the mixed biomass of cassava peels and yam peels biomass as an example. The concentration of Mg in the mixed biomass was 1441 ppm but was 200 ppm and 353 ppm in individual cassava peels and yam peels respectively. The results of this study demonstrated that pretreated mixtures of biomass have varied elemental compositions, which could be an important factor affecting downstream processes, especially if a hybrid feedstock is used in a large-scale application.

Effects of post-washing on pretreated biomass and hydrolysis of the mixture of acetic acid and sodium hydroxide pretreated biomass and their mixed filtrate

Effects of post-washing [one-volume water (I-VW) or double-volume water (Ⅱ-VW)] on pretreated hemp and poplar biomass and enzymatic hydrolysis of the mixture of HOAc and NaOH pretreated biomass and their mixed filtrate were investigated. Compared to I-VW, Ⅱ-VW increased 3.76–6.80% of glucan content in NaOH pretreated biomass, diminished lignin recondensation, and heightened cellulose-related FTIR peak intensities, crystallinity index, and lignin removal. The pH of mixed filtrate was around 4.80, precipitating the NaOH soluble lignin partially. Although Ⅱ-VW showed lower lignin recoveries than I-VW, their FTIR characteristics were equivalent to the commercial alkali lignin. Enzymatic hydrolysis at solid loadings of 2.5–10% (w/v) demonstrated that I-VW and Ⅱ-VW had marginal variations in sugar concentration and conversion efficiency, indicating that I-VW is sufficient for post-washing pretreated biomass. Glucose concentration exhibited a quadratic correlation with solid loading and hemp biomass reached the maximum glucose (43.88 g/L) and total sugar (57.08 g/L) concentrations with I-VW.

Minimizing water consumption for sugar and lignin recovery via the integration of acid and alkali pretreated biomass and their mixed filtrate without post-washing

Excessive post-washing of pretreated biomass leads to huge water consumption and chemical loss. To address this issue, parallel HOAc and NaOH pretreatments of biomass followed by integration of their biomass and filtrate were investigated. Pretreatment effectiveness including morphology, crystallinity, and component recovery, were elucidated. Results showed that HOAc and NaOH in the mixed filtrate were neutralized to achieve a pH of around 4.80 prompting the alkali lignin precipitation. Lignin (46.01 and 48.38 g/kg-biomass for hemp and poplar, respectively) exhibiting comparable FTIR characteristics with the commercial alkali lignin was recovered. Compared to sodium acetate buffer as a control, integrating HOAc and NaOH pretreated biomass and their mixed filtrate for enzymatic hydrolysis boosted total sugar concentration (hemp: 42.90 vs. 38.27 g/L; poplar: 43.18 vs. 38.76 g/L) without compromising glucose yield (hemp: 70.86 vs. 70.69%; poplar: 66.48 vs. 69.48%) but improving xylose yield (hemp: 60.10 vs. 35.92%; poplar: 56.90 vs. 29.39%).

One-step peracetic acid pretreatment of hardwood and softwood biomass for platform chemicals production

Lignocellulosic biomass is an attractive renewable resource to produce biofuel or platform chemicals. Efficient and cost-effective conversion systems of lignocellulosic biomass depend on their appropriate pretreatment processes. Alkali or dilute acid pretreatment of biomass requires a high temperature (> 150 °C) to remove xylan (hemicellulosic sugar) and lignin partially. In this study, peracetic acid was used to pretreat biomass feedstocks, including hardwood and softwood species. It was found that the thermally-assisted dilute acid pretreatment of biomass conducted under the mild temperature of 90 °C up to 5 h resulted in the effective removal of lignin from the biomass with a negligible loss of carbohydrates. This thermally-assisted pretreatment achieved 90% of delignification, and this result was compared with the microwave-assisted pretreatment method. In addition, the crystallinity index (CrI), surface morphology, and chemical structure were significantly changed after the acid pretreatment. The biomass digestibility increased significantly with increased reaction time, by 32% and 23% for hardwood and softwood, respectively. From this study, it is clear that peracetic acid pretreatment is an effective method to enrich glucan content in biomass by delignification.

Development and validation of time‐domain 1H‐NMR relaxometry correlation for high‐throughput phenotyping method for lipid contents of lignocellulosic feedstocks

AbstractThe bioenergy crops such as energycane, miscanthus, and sorghum are being genetically modified using state of the art synthetic biotechnology techniques to accumulate energy‐rich molecules such as triacylglycerides (TAGs) in their vegetative cells to enhance their utility for biofuel production. During the initial genetic developmental phase, many hundreds of transgenic phenotypes are produced. The efficiency of the production pipeline requires early and minimally destructive determination of oil content in individuals. Current screening methods require time‐intensive sample preparation and extraction with chemical solvents for each plant tissue. A rapid screen will also be needed for developing industrial extraction as these crops become available. In the present study, we have devised a proton relaxation nuclear magnetic resonance (1H‐NMR) method for single‐step, non‐invasive, and chemical‐free characterization of in‐situ lipids in untreated and pretreated lignocellulosic biomass. The systematic evaluation of NMR relaxation time distribution provided insight into the proton environment associated with the lipids in the biomass. It resolved two distinct lipid‐associated subpopulations of proton nuclei that characterize total in‐situ lipids into bound and free oil based on their “molecular tumbling” rate. The T1T2 correlation spectra also facilitated the resolution of the influence of various pretreatment procedures on the chemical composition of molecular and local 1H population in each sample. Furthermore, we show that hydrothermally pretreated biomass is suitable for direct NMR analysis unlike dilute acid and alkaline pretreated biomass which needs an additional step for neutralization.

Iron incorporation both intra- and extra-cellularly improves the yield and saccharification of switchgrass (Panicum virgatum L.) biomass

BackgroundPretreatments are commonly used to facilitate the deconstruction of lignocellulosic biomass to its component sugars and aromatics. Previously, we showed that iron ions can be used as co-catalysts to reduce the severity of dilute acid pretreatment of biomass. Transgenic iron-accumulating Arabidopsis and rice plants exhibited higher iron content in grains, increased biomass yield, and importantly, enhanced sugar release from the biomass.ResultsIn this study, we used intracellular ferritin (FerIN) alone and in combination with an improved version of cell wall-bound carbohydrate-binding module fused iron-binding peptide (IBPex) specifically targeting switchgrass, a bioenergy crop species. The FerIN switchgrass improved by 15% in height and 65% in yield, whereas the FerIN/IBPex transgenics showed enhancement up to 30% in height and 115% in yield. The FerIN and FerIN/IBPex switchgrass had 27% and 51% higher in planta iron accumulation than the empty vector (EV) control, respectively, under normal growth conditions. Improved pretreatability was observed in FerIN switchgrass (~ 14% more glucose release than the EV), and the FerIN/IBPex plants showed further enhancement in glucose release up to 24%.ConclusionsWe conclude that this iron-accumulating strategy can be transferred from model plants and applied to bioenergy crops, such as switchgrass. The intra- and extra-cellular iron incorporation approach improves biomass pretreatability and digestibility, providing upgraded feedstocks for the production of biofuels and bioproducts.

Acoustic fields of acid suspensions containing cassava bagasse: Influence of physical properties on acoustic attenuation

The effects produced by high-intensity ultrasound application during the acid pretreatment of biomass can enhance its later conversion into bioethanol. Therefore, it is interesting to evaluate how residues, such as cassava bagasse (CB), affect the actual acoustic field applied and, thus, the magnitude of its effects. For this, calorimetric method was used to estimate acoustic energy and the efficiency of electric-acoustic energy conversion in acid suspensions containing different CB concentrations (2–10%). Tests were carried out under different input powers, from 160 to 400 W (24 kHz), at different distances (1.5–5.5 cm) from the sonotrode. Thus, the experimental acoustic intensity measured varied from 12.90 to 68.57 W·cm−2, the highest values being registered in the suspensions with the lowest CB content (65.55–36.81% of conversion yield close to the sonotrode). Attenuation was also addressed during sound wave propagation, finding a constant value of 0.021 cm−1. Polynomial models were well fitted to acoustic parameters and acoustic intensity exhibited a high correlation (r>0.87 and pvalue ≤ 0.05) with the experimental thermophysical properties of the suspensions.

An understanding for improved biomass pyrolysis: Toward a systematic comparison of different acid pretreatments

Naturally occurring AAEMs in biomass exhibit detrimental effects to biomass pyrolysis as producing less oil with lower quality. Acid pretreatments are cheap and effective methods for mitigating AAEMs effect, thus improving the pyrolysis performance. In the current study, a combination of different experiment techniques and theoretical kinetic analysis was conducted to systematically compare the effects of both acid infusion and washing pretreatments. By utilizing Py-GC/MS system, the product distribution from pyrolysis of raw and acid pretreated corn stovers was obtained. Compared to that of raw corn stover, significant reduction of char and improvement of sugars, especially levoglucosan (55% yield based on cellulose), from pyrolysis of acid washed corn stover were achieved because of the thorough removal of AAEMs in corn stover. As for acid infused corn stover, maintaining reaction in acid buffer condition (3~5 wt% acid infusion) kept the sugar yield at relatively high level. Further increase of acid infusion over 5 wt% resulted in strong dehydration reaction of sugars and sharp decrease of phenolic compounds. The DTG pattern and the key kinetic parameters of corn stover dramatically changed with acid pretreatment. Strong condensation reaction between cellulose and lignin in acid infused corn stover were also suggested by kinetic analysis. Besides, the evolution of major phenolic monomers from lignin component versus temperature was revealed by TG/PI-TOF-MS system. As for acid pretreated corn stover, the agglomeration associated with the increase of char production were further ascribed to the enhanced polymerization of vinyl-phenols and other simple phenols. Overall, the study provides insights into the fast pyrolysis behavior of acid pretreated biomass for producing high-quality bio-oil and value-added chemicals.

Effect of lignin-blocking agent on enzyme hydrolysis of acid pretreated hemp waste.

Hemp wastes (stems and branches), fractionated after hemp flower extraction for the production of cannabidiol oil, were utilized as a potentially renewable resource for the sugar flatform process. Hydrolysis of cellulose from the acid pretreated hemp biomass using a commercial enzyme was tested and evaluated for its chemical composition, morphological change, and sugar recovery. Acid pretreated hemp stems and branches, containing 1% glucan (w/v) solids, were hydrolyzed for 72 h using 25 mg enzyme protein per g glucan. A 54% glucose conversion was achieved from the treated branches versus a 71% yield from the treated stems. Raw branches and stems yielded 35% and 38% glucose, respectively. Further tests with a lignin-blocking additive (e.g. bovine serum albumin) resulted in a 72% glucose yield increase for stem hydrolysis using 10 mg enzyme protein per g glucan. While pretreatment promotes amorphous hemicellulose decrease and cellulose decomposition, it causes enzyme inhibition/deactivation due to potential inhibitors (phenols and lignin-derived compounds). This study confirms the addition of non-catalytic proteins enhances the cellulose conversion by avoiding non-productive binding of enzymes to the lignin and lignin-derived molecules, with lignin content determining the degree of inhibition and conversion efficiency.

Evaluation of Sulfuric Acid-Pretreated Biomass -Derived Biochar Characteristics and its Diazinon Adsorption Mechanism

Evaluation of Sulfuric Acid-Pretreated Biomass -Derived Biochar Characteristics and its Diazinon Adsorption Mechanism

Two Nonnegligible Factors Influencing Lignocellulosic Biomass Valorization: Filtration Method after Pretreatment and Solid Loading during Enzymatic Hydrolysis

Valorization of lignocellulosic biomass into biofuels has received considerable attention for decades with tremendous thermochemical pretreatments proposed. However, inconsistencies among studies in lignin removal can often be misleading and even violate the chemical mechanism, which might be attributed to the variation in the filtration method used after pretreatment. A phenomenon, promoting pretreatment strategies based on sugar conversion efficiency or yield only from single and random low-solid enzymatic hydrolysis, was also observed. Herein, the effects of filtration methods using a slow drip metal filter (SDMF) with an aperture of 0.2 mm and Whatman grade 4 filter paper (WGFP) with an aperture of 20–25 μm under vacuum filtration after liquid hot water (LHW), acid, and alkali pretreatments on the chemical composition of the solid and liquid, sugar recoveries, and lignin removal and solid loading (2–15%) on enzymatic hydrolysis of corn stover and poplar wood were investigated. Results showed that SDMF increased the glucan content (1.1–3.0%) in pretreated biomass and induced solid loss (3.8–12.6%) into the filtrates, resulting in lower sugar recoveries and overestimated lignin removal compared to WGFP. 5-Hydroxymethylfurfural (HMF) and furfural derived from sugar degradation triggered pseudolignin formation, inducing a negative lignin removal for both LHW and acid pretreated biomass. In comparison, alkali pretreatment neutralized the weak acids released from sugar decomposition and achieved a robust delignification (67.8–90.8%). Solid loading used for enzymatic hydrolysis of pretreated biomass determined sugar concentration, conversion efficiency, and yield. This result indicates that promoting pretreatment technologies based on sugar conversion efficiency or yield of enzymatic hydrolysis at low solid loading may be misleading. This work demonstrates that the filtration method used for solid and liquid separations after pretreatment and solid loading for enzymatic hydrolysis should be cautiously selected and implemented when valorizing biomass into biofuels.

Different acid pretreatments at room temperature boost selective saccharification of lignocellulose via fast pyrolysis

Fermentable sugars are a group of pivotal intermediates and platform compounds achieved by the conversion of lignocellulose. Fast pyrolysis, as a little-explored way to liberate levoglucosan from biomass, may have a potential capability to overcome the technical barriers and fundamental limitations for efficient saccharification. Pretreatment prior to fast pyrolysis is essential to improve levoglucosan yield from lignocellulose. Contrary to typical high-temperature acid pretreatments, a pretreatment under mild conditions was evaluated and optimized, where different acid (formic acid, acetic acid, oxalic acid, nitric acid, phosphoric acid, sulphuric acid and hydrochloric acid) were employed at room temperature prior to fast pyrolysis of lignocellulose. Due to the alteration of chemical compositions and physical structures of biomass, especially the elimination of alkali and alkaline earth metals, the levoglucosan yield of dilute acid pretreated biomass was improved remarkably as compared with that of raw material, meanwhile claimed that acid pretreatments at room temperature had an enough capability in efficient utilization of biomass. In sum, this study offered a novel and economical strategy for selective saccharification of lignocellulose for industrialized bio-refinery.

Promotion of enzymatic hydrolysis of lignocellulosic biomass using natural additives for bioethanol production

AbstractPretreatment is used to reduce the lignin and hemicellulose content present in biomass as they are inhibitory to the hydrolysis of cellulose. As time proceeds, it is found that redeposition of lignin occurs on the biomass surface. This paper focuses on the preparation of natural additives using soy‐protein extract, and it is used for the enhancement of enzymatic hydrolysis. Acid pretreatment followed by hydrogen peroxide and hot‐water pretreatment has been attempted for the black urad dhal (Vigna mungo) biomass. Hot‐water–pretreated biomass was further subjected to enzymatic hydrolysis using additives. The nonproductive lignin binding on to the surface of the biomass lowers the activity of the enzyme and increases the requirement of enzymes for the hydrolysis of cellulose. The hydrolyzed biomass subjected to bioethanol production using saccharomyces cerevisiae. It is noticed that the bioethanol produced using hot‐water pretreatment with additives and acid pretreated biomass with additives has a concentration of about 0.443 and 0.204 mL/g, respectively.

Investigation of Rheological Behavior of Untreated and Microwave-Assisted Alkaline Pretreated Sugarcane Straw for Biofuel Production

Biomass slurries, such as those subjected to microwave-assisted alkaline (MAA) pretreatment, will become common substrates for the production of biofuels in the future. While the rheology of acid and ionic liquid pretreated biomass is known, the rheology of alkaline pretreated biomass is not yet reported; hence, the goal of this study was to establish the rheological characteristics of untreated and MAA pretreated sugarcane straw (SC). Using rotational rheometry and rheological models, the rheology of SC slurries was assessed as a function of particle size and insoluble solids concentration. In the range of 5–17% insoluble solids concentration, the slurries were consistently pseudo-plastic (n = 0.33 ± 0.02), possessed yield stress with their flow accurately described by the Casson rheological model (R2 = 0.98–0.99). The apparent viscosity and yield stress increased by two orders of magnitude with an increase in insoluble solids concentration. Essentially, MAA pretreated slurries exhibited significantly higher values of apparent viscosity and yield stress than the untreated ones, in the range of 55–80% and 21–63% for particle sizes of < 63 µm (P63) and 90–180 µm (P90), respectively. Pretreated P63 samples exhibited higher apparent viscosity and yield stress than the P90. On the other hand, for untreated samples, P63 samples had a reduced apparent viscosity than P90 samples. The results of this study definitively reveal that MAA significantly increases the shear rate dependent shear viscosity values along with the yield stress of biomass slurries. This will, therefore, serve as a benchmark for characterizing other MAA pretreated biomass slurries to guide the design of industrial-scale production equipment.

Azo dye removal by acid pretreated biomass and its regeneration by visible light photocatalysis with incorporated CuO

ABSTRACT In this work, we synthesized self-regenerative biosorbent BM-H3PO4-(CuO) by combining the photocatalyst CuO and acid pre-treated biomass (BM-H3PO4), the hybrid material BM-H3PO4-(CuO) was used for the removal of azo dye Direct Red 89 (DR-89). The morphology, texture phase, composition of the samples was characterized with scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, elemental diffraction analysis X-ray (EDAX). That confirms the presence of CuO into the pretreated biomass BM-H3PO4. The results reveal that when the biomass was loaded with a proper CuO/BM-H3PO4 weight ratio of 60%, the biosorption capacity was enhanced to 5.5 times compared to BM-H3PO4. The maximum adsorption capacity of BM-H3PO4-(CuO)60% was 30.3 mg g−1 determined from the Langmuir isotherm. The pseudo-second-order kinetic model was more appropriate for describing dye biosorption. The hybrid material BM-H3PO4-(CuO)60% demonstrated a better photocatalytic activity under visible light irradiation then pure CuO. Incorporation of the CuO particles into the biosorbent, offers the possibility to harvest visible light for oxidative photodegradation. The prepared material also showed good reusability in the cyclic of biosorption–photocatalysis experiments and the biosorption efficiency was higher than 90% over four cycles. This study provides an eco-friendly way to fabricate self-regenerative biosorbents.

Simultaneous Catalytic Conversion of Acid-Pretreated Biomass into High-Quality Syngas and Bio-oil at Mild Temperature

An innovative method for the coproduction of high-quality bio-oil and syngas via the integration of in situ acid pretreatment on feedstock and ex situ reforming by activated carbon catalyst was inv...