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Graphical abstract:

Nanocrystalline cellulose (NCs) was successfully isolated from pepper biowaste using lactic acid hydrolysis and employed as filler in seaweed biocomposite. Optimization of hydrolysis parameters by employing response surface methodology (RSM) generates 75.50 % NCs with 76.68 % crystallinity at 6.31 M lactic acid, 3.02 h and 85.86 °C. The ANOVA analysis indicates hydrolysis efficiency requires precise temperature control and lactic acid concentration to obtain high crystalline cellulose at high production yield. The NCs displayed rod-shaped morphology with 29.65 ± 3 nm diameter and 335.19 ± 10 nm length, with a negative zeta potential and higher thermal stability than the cellulose. NCs addition as filler in seaweed biofilm improved the tensile strength but reduced the elongation at break. The biofilm exhibits excellent properties in reducing water adsorption, solubility, and water permeability by increasing nanocellulose filler.

•Different metal promoters result in different selectivity of the C1(methanol and methane) and C2+(olefin) products on CO2hydrogenation.•Metal promoters modify the hydrogen dissociation potential and surface oxygen vacancy.•Promoter will be able to stabilize the intermediate and to maneuver catalytic reaction pathway into desired products for CO2hydrogenation to longer chain molecules.

Cellulose nano fibril (CNF) can be selected as an agent of pickering emulsion in biofoam manufacture. This study thoroughly investigates the pickering emulsion method for producing biofoam, the characterization of CNF from pineapple leaves, the production of biofoam with various concentration of CNF and surfactant, and the effect of these parameters on the properties of wet foam and dry foam. CNF was created by mechanical grinding then the stability and morphology were evaluated. The pickering emulsion mechanism in biofoam manufacture was investigated using foamability and foam stability with various CNF and surfactant concentration. As the results, CNF concentrations will create varying zeta potential values. The morphology of CNF shows that it has a structure-like entangled network. The stability test demonstrates that adding CNF improves the stability and foamability of biofoam by the pickering effect. Biofoam without CNF has an unstable structure and is easily collapse when dried in an oven. The concentration of CNF and the amount of surfactant utilized altered the qualities of both wet and dry foam. The lower concentration of CNF and the addition of surfactant could increases foamability, high porosity, water absorption, and biodegradability; as well as low density, contact angle and bending characteristics. In biofoam that consists of 2 % CNF, the stability of wet foam increases as the amount of surfactant added, resulting in a biofoam with low tensile strength.

Lactic acid recovery and reusability for hydrolysis of cellulose offers an economical method and produces fewer waste streams. Successful lactic acid recovery up to three recycle times efficiently hydrolyzed NCs with rod-shape morphology. However, after four cycles, the nanocrystalline cellulose yield reduced from 72.3 % to 48.2 %, forming large nanocelluloses with high crystalline index. Large-size nanocellulose with high zeta potential and thermal stability were obtained with increasing cycles due to inefficient acid diffusion into the rigid crystalline network compared to amorphous cellulose. This study offers a green pathway for hydrolysis nanocellulose using a less corrosive and low toxicity lactic acid than inorganic acids.