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Bamboo is a perennial rapid-growing plant that is given preference for renewable biosources for biofuels and bio-based chemical conversion. Bamboos are rich in cellulose and have highly recalcitrant biomass due to high lignin. Bamboo is abundantly available in Northeastern India and can be utilized as a feedstock biofuels. Here, we evaluated the pretreatment of bamboo residues Dendrocalamus strictus with different concentrations of alkali, hydrogen peroxide, and alkaline hydrogen peroxide and its influence on biomass digestibility for enhancement of sugar recovery with Celic C cellulase enzyme blend. Enzymatic hydrolysis data indicated untreated raw biomass showed a digestibility of 40% after 48 h of incubation. The biomass pretreated with alkali showed a maximum digestibility of 61% obtained from 10% loaded with 0.5% w/v NaOH. Pretreatment of the bamboo with H2O2 shows a maximum digestibility of 75% from biomass loaded with 1% w/v of H2O2. Combinational pretreatment of alkaline hydrogen peroxide showed a maximum efficiency of biomass digestibility of 83% attained from biomass loaded with 1% w/v NaOH-H2O2. Crystallinity index (CrI) analysis showed that CrI increased from 64% to 70.75% in pretreated biomass. FTIR and SEM analysis show changes in functional groups, morphology, and surface of biomass in pretreated biomass. Compositional analysis shows that 68% of lignin removal is obtained from alkaline hydrogen peroxide pretreatment. Cellulose content increased from 52% to 65%, and hemicellulose decreased from 18.6% to 8.6%. Results indicated that the potential possibility of bamboo waste biomass as feedstock for biorefinery products and alkaline hydrogen peroxide pretreatment methods is an efficient strategy for sugar recovery for bioethanol production. [ABSTRACT FROM AUTHOR]

This study investigated the biphasic phenoxyethanol–citric acid (PECA) pretreatment for bamboo residues (BRs) and its corresponding effects on the enzymatic hydrolysis performance. It is found that increasing the concentration of citric acid in the pretreatment system from 2.5% to 15% greatly enhanced the delignification and xylan removal for BRs. Consequently, the enzymatic hydrolysis yield of pretreated BRs significantly enhanced, increasing from 12.4% to 58.2% and 28.0%72.4% when the concentration of citric acid was increased from 2.5% to 15.0% at 160°C and 170°C, respectively. The characterization results from cellulose crystallinity, accessibility, and hydrophobicity of pretreated bamboo residues indicated that their changes possessed a beneficial performance on the enzymatic hydrolysis yield, which could result from the synergistic removal of lignin and xylan. The Chrastil model analysis showed that pretreatment at higher conditions resulted in the pretreated BRs possessing weaker diffusion resistance for cellulase, which is attributed to its higher enzymatic hydrolysis yield.

Bamboo is a perennial rapid-growing plant that is given preference for renewable biosources for biofuels and bio-based chemical conversion. Bamboos are rich in cellulose and have highly recalcitrant biomass due to high lignin. Bamboo is abundantly available in Northeastern India and can be utilized as a feedstock biofuels. Here, we evaluated the pretreatment of bamboo residues Dendrocalamus strictus with different concentrations of alkali, hydrogen peroxide, and alkaline hydrogen peroxide and its influence on biomass digestibility for enhancement of sugar recovery with Celic C cellulase enzyme blend. Enzymatic hydrolysis data indicated untreated raw biomass showed a digestibility of 40% after 48 h of incubation. The biomass pretreated with alkali showed a maximum digestibility of 61% obtained from 10% loaded with 0.5% w/v NaOH. Pretreatment of the bamboo with H2O2 shows a maximum digestibility of 75% from biomass loaded with 1% w/v of H2O2. Combinational pretreatment of alkaline hydrogen peroxide showed a maximum efficiency of biomass digestibility of 83% attained from biomass loaded with 1% w/v NaOH-H2O2. Crystallinity index (CrI) analysis showed that CrI increased from 64% to 70.75% in pretreated biomass. FTIR and SEM analysis show changes in functional groups, morphology, and surface of biomass in pretreated biomass. Compositional analysis shows that 68% of lignin removal is obtained from alkaline hydrogen peroxide pretreatment. Cellulose content increased from 52% to 65%, and hemicellulose decreased from 18.6% to 8.6%. Results indicated that the potential possibility of bamboo waste biomass as feedstock for biorefinery products and alkaline hydrogen peroxide pretreatment methods is an efficient strategy for sugar recovery for bioethanol production.

Bamboo is considered a renewable energy bioresource for solving the energy crisis and climate change. Dendrocalamus branddisii (DB) was first subjected to sulfomethylation reaction at 95°C for 3 h, followed by Fenton oxidation pretreatment at 22°C for 24 h. The synergistic effect of combined pretreatment dramatically improved enzymatic digestibility efficiency, with maximum yield of glucose and ethanol content of 71.11% and 16.47 g/L, respectively, increased by 4.7 and 6.11 time comparing with the single Fenton oxidation pretreatment. It was found that the hydrophobicity of substrate, content of surface lignin, degree of polymerization, and specific surface area have significant effects on the increase of enzymatic saccharification efficiency. It also revealed that sulfomethylation pre-extraction can improve the hydrophilicity of lignin, leading to the lignin dissolution, which was beneficial for subsequent Fenton pretreatment of bamboo biomass. This work provides some reference for Fenton oxidation pretreatment of bamboo biomass, which can not only promote the utilization of bamboo in southwest China, but also enhances the Fenton reaction in the bamboo biorefinery.

• Exploring the economic feasibility of biphasic pretreatment technology. • High-value lignin-based adhesive can bring significant economic benefits. • Trade-offs between product yield and economic performance are revealed. • Key drivers of economic feasibility are identified. This study conducted a techno-economic analysis to assess the economic feasibility of a biorefinery converting bamboo residues to bioproducts via phenoxyethanol-acid pretreatment. The analysis is integrated with a rigorous process simulation model with the support of experiment data. The bioproducts include ethanol or polylactic acid (PLA), with lignin-based wood adhesive as the byproduct. The minimum selling price (MSP) is $515-$819 per t ethanol and $1,512-$1,842 per t PLA when biphasic treatment is deployed, compared to the MSP of $2,318-$2,721 per t ethanol and $2,859-$3,211 per t PLA for no biphasic pretreatment. Adopting a ratio of 1:1 phenoxyethanol: acid solution (1%) in pretreatment decreases the final product yield but leads to lower MSP than 4:1 phenoxyethanol: acid solution (1%) due to lower phenoxyethanol consumption. A sensitivity analysis identifies the key drivers of reducing MSP, including increasing economic gain from the lignin-based wood adhesive, lowering the phenoxyethanol cost, and expanding plant capacity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Producing ethanol, PLA, and wood adhesive from bamboo residues. • Exhibiting the environmental benefits of biphasic pretreatment technology. • Trade-off between product yield and environmental impacts are revealed. • High-value lignin-based adhesive can bring environmental benefits. • Key drivers of environmental performance are identified. Utilizing bamboo residues to produce decarbonization energy products or materials diverts wastes from low-value treatment and supports the circular bioeconomy at the same time. This study develops a cradle-to-grave life-cycle assessment (LCA) for a biorefinery converting bamboo residues into bioproducts (ethanol, polylactic acid (PLA), and bio-based wood adhesive) in China. To combat the low enzymatic hydrolysis performance of bamboo residues and valorize the lignin, this study adopts a biphasic pretreatment by coupling phenoxyethanol and sulfuric acid solution (1%) to achieve high fermentable sugar production. The LCA study is coupled with a process simulation for an industrial-scale biorefinery based on the experimental data. Our results show that the life-cycle Global Warming Potential (GWP) is 17.0–32.1 gCO 2 e/MJ for ethanol cases and 3.2–3.7 kgCO 2 e/kg for PLA cases, when biphasic pretreatment is adopted. The lower GWP values are achieved by using 1:1 phenoxyethanol: acid solution, though it has a lower product yield than 4:1 phenoxyethanol: acid solution cases. Without biphasic pretreatment, the GWP is 135.8 gCO 2 e/MJ ethanol and 4.4 kgCO 2 e/kg PLA. For the perspective of treating 1 dry t bamboo residues, with biphasic pretreatment, the GWP is −174 to −66 kgCO 2 e for ethanol cases and −542 to −432 kgCO 2 e for PLA cases. The lower GWP is also from using 1:1 phenoxyethanol: acid solution (1%). These GWP ranges are lower than conventional landfilling (2969 kgCO 2 e) and landfilling with landfill gas recovery (−28 kgCO 2 e). [ABSTRACT FROM AUTHOR]

Abstract This study investigated the physical and mechanical properties of six groups of bamboo–wood composites (BWC) made from bamboo and wood wastes, which are produced from the industry processing in Taiwan. Results obtained from non-destructive testing (NDT) indicated that the boards made with 100% bamboo residues (Group B) revealed higher ultrasonic-wave velocity (V u) and tap tone sound velocity (V t) than other BWC boards. Both V u and V t of composite boards were proportional to the ratio of bamboo residues contains. Three-layer composites made with bamboo/wood/bamboo residues at 1:2:1 ratio (Group B/2W/B) had the highest specific strength as well as modulus of elasticity (MOE) and modulus of rupture (MOR) among all the composites. B/2W/B composite board had structural characteristics similar to those of medium-density fiberboards (MDF) and particleboards; thus, it might have better compression resistance than other types of boards. B/2W/B composite board also had the highest screw holding strength (SHS); next was the boards composed entirely of woody wastes (Group W). The results obtained from analysis of water absorption rate (WA%) show a positive correlation with porous bamboo contents; meanwhile, wood chips have higher water-absorption swelling rate than bamboo residues. Hence, it showed greater change in thickness swelling coefficient (TS%) and volume swelling coefficient (S%).

This study focused on the assessment of gas emissions and bioenergy potential of the combustions of bamboo leaves (BL), shoot leaves (BSL) and branches (BB) in the air atmosphere. The main combustion stage of the three residues occurred at between 200 and 600 °C, with three peaks of mass loss. The pattern of mass loss rate was BSL > BB > BL, with BSL having the best combustion characteristic parameters. The main evolved gases were CO 2 and H 2 O at between 200 and 600 °C. Organic gaseous compounds were decomposed in the range of 200–400 °C. Air pollutants were produced in the range of 200–500 °C. N-containing gas pollutants were 0.01–0.1 times CO 2 , while SO 2 was produced in a very small amount. BL produced more gas pollutants than did BSL and BB, while the controls over the gas pollutants should be more concentrated in the range of 200–400 °C. The joint optimizations of derivative thermogravimetry, differential scanning calorimetry, remaining mass, and conversion degree showed 653.2 °C and 5 °C/min as the optimum operational conditions for bioenergy utilization, while BB performed as the best feedstock. Among three iso-conversion methods used to estimate activation energy, Flynn-Wall-Ozawa led to best correlation. The Coats-Redfern method pointed to the second order reaction model (f (α) = (1− α)2) as the most likely reaction mechanism. Overall, the bamboo residues were promising as the environmentally friendly and renewable feedstock. Our findings can provide the basis for bioenergy generation, pollution control, and optimal efficiency when the industrial-scale combustions of the bamboo residues are adopted. Image 1 • Combustion behaviors of three bamboo residues were compared for four heating rates. • Their bioenergy generation potential was rated as BSL > BB > BL. • Gas products were mostly CO 2 and H 2 O, and rarely NO x and SO 2. • Kinetic triplets indicated the different mechanisms of the residues. • Four responses were jointly optimized using temperature, heating rate and residue type. [ABSTRACT FROM AUTHOR]

Nitrogen-enriched activated carbons prepared from bamboo residues were characterized by means of BET, XPS, and elemental analysis. Then adsorption experiments were carried out to study the effects of various physicochemical parameters such as contact time, temperature, pH, and initial concentration. Adsorption equilibrium was achieved within 120 min at a phenol concentration of 250 mg/L. When the pH was 4 and 0.1 g of the carbon absorbent and 100 mL of phenol solution at 250 mg/L were used, the phenol adsorption of the ACs with melamine and urea modifications were 219.09 mg/g and 214.45 mg/g, respectively. Both were greater than the capacity of unmodified AC, which was 163.82 mg/g. The Langmuir isotherm adsorption equation well described the experimental adsorption isotherms. The adsorption kinetics was well explained by pseudo-second-order kinetics rather than the pseudo-first-order. In conclusion, the nitrogen-enriched activated carbon proposed as adsorbents of the phenol wastewater were shown to be effective, which also means that bamboo residues have promise as activated carbon precursors for liquid phase adsorbents for environmental protection.

Detailed kinetic triplets and thermodynamic studies of the three main components are important in the efficient design of the pyrolysis process. In this work, the three main components (cellulose, hemicellulose and lignin) of lignocellulosic biomass were extracted from bamboo residues (BR). The kinetic triplets and thermodynamic parameters of BR and its three components were then interpreted using thermogravimetric analysis. Three iso-conversional methods (Friedman, Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose models) estimated the average activation energy of BR and the extracted cellulose, hemicellulose and lignin to be 164.5, 145.3, 186.0 and 182.7 kJ mol−1, respectively. The frequency factors of BR ranged from 1013 to 1018 min−1 according to the Kissinger method, and the average frequency factors of the three main components were cellulose < hemicellulose < lignin. The master plots reveal the dominance of the diffusion mechanism in the pyrolysis process. The change in enthalpy (109.5–297.1 kJ mol−1) and Gibb free energy (138.7–156.3 kJ mol−1) indicated the endothermic and non-spontaneous nature of the pyrolysis of BR and the three main components. Kinetic and thermodynamic analyses confirmed the feasibility of BR as a potential candidate for bioenergy. [Display omitted] • The kinetics triplets of bamboo residues and its three extracted components were studied. • The activation energy of bamboo residues varies between 142.95 and 201.23 kJ mol−1. • The frequency factors of bamboo residues ranged from 1013 to 1018 min−1. • The dominance of the diffusion mechanism in the pyrolysis process was revealed. • Thermodynamic parameters of bamboo residues and its components were proposed. [ABSTRACT FROM AUTHOR]

Nitrogen-enriched activated carbons prepared from bamboo residues were characterized by means of BET, XPS, and elemental analysis. Then adsorption experiments were carried out to study the effects of various physicochemical parameters such as contact time, temperature, pH, and initial concentration. Adsorption equilibrium was achieved within 120 min at a phenol concentration of 250 mg/L. When the pH was 4 and 0.1 g of the carbon absorbent and 100 mL of phenol solution at 250 mg/L were used, the phenol adsorption of the ACs with melamine and urea modifications were 219.09 mg/g and 214.45 mg/g, respectively. Both were greater than the capacity of unmodified AC, which was 163.82 mg/g. The Langmuir isotherm adsorption equation well described the experimental adsorption isotherms. The adsorption kinetics was well explained by pseudo-second-order kinetics rather than the pseudo-firstorder. In conclusion, the nitrogen-enriched activated carbon proposed as adsorbents of the phenol wastewater were shown to be effective, which also means that bamboo residues have promise as activated carbon precursors for liquid phase adsorbents for environmental protection. [ABSTRACT FROM AUTHOR]

In this study, bamboo residues derived functional hydrochar microspheres have been fabricated by different acids-assisted hydrothermal carbonization including hydrochloric aicd, sulfuric acid or nitric acid.The energy-dispersive X-ray fluorescence spectroscopy and Fourier Transform Infrared spectroscopy analyses showed that sulfur- and nitrogen-containing functional groups were grafted on the surface of hydrochar microspheres, respectively. Elemental analysis indicates that the addition of acids has a significant influence on the hydrothermal reaction pathway and promotes the hydrolysis process. When the hydrothermal carbonization temperature is 220 °C, hydrochloric acid and nitric acid can effectively overcome the agglomeration of hydrochar microspheres and form single micron carbon sphere. Irregularly shaped hydrochar particles groups were formed during sulfuric acid-assisted hydrothermal treatment. The results indicate the viability of acid assisted hydrothermal carbonization to produce the functional hydrochar microsphere using bamboo residues. • Acids changed hydrothermal reaction pathway and accelerated hydrolysis process. • HCl and HNO 3 aided hydrothermal treatment overcome hydrochar spheres agglomeration. • Sulfuric and nitrogen groups were grafted on the surface of hydrochar microspheres. [ABSTRACT FROM AUTHOR]

The catalytic combustions of bamboo leaves (BL) and branches (BB) with textile dyeing sludge ash (SA), Fe 2 O 3 , and CaO were qualitatively analyzed using thermogravimetric and Fourier transform infrared spectroscopy analyses, and thermodynamic equilibrium simulations. The catalysts (Fe 2 O 3 > SA > CaO) exerted a more pronounced effect in the char combustion (third) stage and enhanced the volatiles and comprehensive combustion indices with 40 °C/min. The catalysts (CaO > SA > Fe 2 O 3) reduced C- and N-containing gas emissions in the devolatilization (second) stage. CaO elevated the N-containing gas emission in the third stage, whereas Fe 2 O 3 and SA inhibited the formation of NO precursors. BB presented a higher risk of slagging than did BL, while the improved empirical indices of the ash deposition pointed to CaO as the optimal catalyst. Our simulations showed the final ash components of BL and BB were mainly as SiO 2 and K 2 Si 4 O 9. The addition of CaO alone helped to form a high-melting point Ca-silicate. Although the addition of Fe 2 O 3 had no effect on the ash conversion, SA reduced the formation of K-silicate in the ash. The catalysts (CaO > SA > Fe 2 O 3) reduced the activation energy. Overall, the catalytic combustions improved the bioenergy and the N-containing gas emissions. SA as a Fe and Ca-rich industrial waste enhanced the combustion performance in terms of reductions in waste streams, gas emissions, and ash deposition. Our results supplied new insights into the efficient and clean bioenergy production of bamboo residues, and the waste utilization of SA. Image 1 • Two bamboo residues were combusted using sludge ash (SA), CaO and Fe 2 O 3 catalysts. • Catalysts increased volatiles and combustion performances with a high heating rate. • Catalytic emission reductions in NH 3 and NO were CaO > SA > Fe 2 O 3. • The conversion of K–SiO 2 was affected by CaO and SA but not by Fe 2 O 3. • CaO reduced the activation energy the most. [ABSTRACT FROM AUTHOR]