Phosphoric Acid Hydrolysis Research Articles

Highly-efficient method for chitin nanocrystal production using solid-state phosphoric acid hydrolysis

Highly-efficient method for chitin nanocrystal production using solid-state phosphoric acid hydrolysis

Extraction of cellulose nanocrystalline from Camellia oleifera Abel waste shell: Study of critical processes, properties and enhanced emulsion performance

Cellulose nanocrystals (CNCs) extracted from the waste shell of Camellia oleifera Abel (C. oleifera) are gaining attention as valuable materials. In this study, CNCs were extracted from the agricultural waste shell of C. oleifera through phosphoric acid and sulfuric acid hydrolysis, respectively. Firstly, we optimized the alkaline treatment process for cellulose isolation by using response surface methodology. Furthermore, the properties of CNCs were investigated by neutralizing them with NaOH and NH3·H2O, and by dialysis in water. In addition, the characterization methods including FT-IR, TGA, AFM and TEM were used to analysis the properties of the synthesized CNCs. Finally, CNCs were studied for their application in essential oil-based Pickering emulsions. CNCs obtained from sulfuric acid showed the smallest particle size and good dispersibility. Moreover, the release profiles of essential oils in the emulsions were followed by Peppa's kinetic release model. The antibacterial activity of the emulsions against E. coli and S. aureus showed that CNCs-stabilized emulsions enhanced the antibacterial activity of essential oils. Therefore, neutralization treatments may enhance the properties of CNCs, and CNCs stabilized Pickering emulsions can enhance antibacterial activity of essential oil. This study provides insight into the potential application of CNCs derived from C. oleifera waste shells.

Quantitative analysis of the formation of monodisperse cello-oligomers obtained by phosphoric acid hydrolysis

Hydrolysis of cellulose in concentrated phosphoric acid is known to give two distinctive mono-disperse cello-oligomers: the degree of polymerization (DP) of 7 and 15. To understand the formation mechanism of monodisperse cello-oligomers, the transition of DP during phosphoric hydrolysis was monitored by size-exclusion chromatography combined with multiangle laser-light scattering analyses (SEC/MALLS). The obtained results suggested that not the hydrolysis at a specific length but random hydrolysis was likely. The rate of hydrolysis slowed down when the DP reached around 40, and the pool of cello-oligomers appeared at the incubation of 35 days. Then, the mono-disperse cello-oligomers were recovered from the pool of cello-oligomers by fractionation based on the solubility difference.

Kinetic analysis of wet process phosphoric acid hydrolysis of corncob

Kinetic analysis of wet process phosphoric acid hydrolysis of corncob

Controllable self-assembly of cellulose nanospheres through phosphoric acid triggered dissolution-regeneration and degradation

Phosphoric acid has been utilized as a favorable alternative to strong acids for the production of cellulose nanospheres (CNS) in recent years, partly owing to the reduced reliance on mechanical assistance. In the present study, phosphoric acid hydrolysis was applied to synthesize CNS from natural cotton pulp. Compared to reported long-time hydrolysis over 12 h, reduced time of 4 h is achieved for CNS production. Particle size from 530 nm to 1.3 μm was further controlled by changing the hydrolysis time in 4–11 h. Powdered sample was obtained after freeze-drying. CNS prepared in this work exhibits a cellulose II structure. Crystallinity index of the samples locates in 70–75 % which is higher than the reported 43–60 % for the acid-hydrolyzed medical cotton. Moreover, compared to the sulphuric-acid hydrolyzed CNS with higher crystallinity, thermal stability of the CNS generated from phosphoric-acid hydrolysis is significantly greater. A cooperative dissolution-regeneration and degradation is proposed to induce CNS self-assembly. Initial cellulose microfibrils are completely dissolved as exposed to phosphoric acid. Partial chains aggregate as a result while the remaining chains assemble onto the aggregates in a layer-by-layer manner. Acid degradation to cellulose with time affects length of the molecular chains. CNS size is controlled accordingly.

Valorization of cannabis green waste to cellulose nanomaterials via phosphoric acid hydrolysis

The recent increases in Cannabis sativa (cannabis) production, both in industrial hemp and recreational varieties, has highlighted the need for low-impact and sustainable practices for this expanding industry. Green waste of cannabis, consisting of the vegetative components like plant stalks, offers an unexplored opportunity for valorization through biomass optimization. Like hemp, recreational cannabis varieties contain two high cellulose fiber types: bast fiber (phloem tissue) and hurd fiber (xylem tissue). Using hemp as a model for recreational cultivars, this study demonstrates the ability to isolate cellulose nanomaterials from both bast and hurd fiber through phosphoric acid hydrolysis. Scanning electron microscopy (EM) shows that sodium hydroxide treatment is required for removing all non-cellulose surface components from hurd fiber. Comparison of the two fiber types with transmission EM reveals phosphoric acid-hydrolyzed bast fibers produce cellulose nanocrystals (CNC), while hurd fibers are more prone to producing a mixture of cellulose nanocrystals and nanofibril-like particles (CNF) without chemical pretreatment. Adding hydrogen peroxide to the sodium hydroxide pretreatment decreased the variation in CNC sizes resulting from both bast and hurd. The findings of this study provide several avenues for valorization of green waste, while aiming to minimize the techno-economic impact of pretreatments.

Controlled Chitosan Molecular Weight Reduction by Mechanochemical and Aging-Based Phosphoric Acid Hydrolysis

Chitosan is typically produced by the deacetylation of the chitin biopolymer. Its molecular weight (Mw) is a function of the chitin source and the deacetylation conditions. It remains a challenge to both control the Mw of chitosan and obtain good monodispersity, which are essential for optimal function of chitosan in different applications. This study explores the use of mechanochemistry and aging as effective methods toward the controlled reduction of the Mw of commercial high Mw chitosan (HMwChs) with phosphoric acid, where Mw was measured by gel permeation chromatography (GPC). In comparison to conventional solution-based methods, this new mechanochemical method features improved process mass intensity in comparison to conventional techniques and affords low Mw chitosan (LMwChs) samples in a range of 200 to 19.5 kDa, with a polydispersity down to1.8.

Producción de azúcares por hidrólisis ácida diluida del bagazo de avena con tres ácidos diferentes: cinética y termodinámica

Acid hydrolysis is used as a treatment method to hydrolyse the polysaccharides present in biomass to fermentable sugar. In this research the hydrolysis of oat bagasse was studied employing different inorganic acids (HCl, H2SO4 and H3PO4) at low temperatures (90 – 110 °C) in a long-term process. Sulphuric acid showed a high potential to produce reducing sugars reaching the maximum production yields at 110°C, while hydrochloric acid at 110°C was the most catabolic acid promoting sugars transformation into furfural. FTIR and relative transmittance analyses suggested that major impact on lignin polymer was made by phosphoric acid hydrolysis at Combined Severity Factors (CSF) higher than 1.5. Kinetic constants calculated from conventional Saeman model allowed to determine thermodynamic parameters for each inorganic acid. Decomposition of sugars occurred most frequently when the Activation Energies (Ae) were low than calculated for sugar production, being aldehydes, the most stable products obtained during hydrolysis. Thermodynamic parameters show and endothermic and non-spontaneous oat bagasse hydrolysis reaction for different inorganic acids.

Rheological properties of cellulose nanocrystal suspension

Cellulose nanocrystal (CNC) is a unique nanomaterial that have received considerable attention due to its good individual mechanical properties and was proven as a good reinforcing filler to various polymer matrix. Thermoplastic polyurethane (TPU), have been widely used for lots of application like automobile, aerospace and medical industries. However, because of its chemical structure, TPU have significant deficiencies like low tensile strength as working with high force application. Thus, CNC has been used to overcome this limitation. This research was conducted to investigate the rheological properties of CNC in TPU and water matrix. CNC were obtained from microcrystalline cellulose (MCC) via sulphuric (CNC-S) and phosphoric (CNC-P) acid hydrolysis. CNCs (1 wt%, 2 wt% and 5 wt%) were dispersed in TPU and water matrix. CNC produced and its suspension were undergoing Field Emission Scanning Electron Microscopy (FESEM) and rheological test to identify the morphology and rheological behaviour respectively. CNC-S obtained has diameter of 17 ± 4 nm and length of 225 ± 100 nm, while CNC-P has diameter of 20 ± 5 nm and length of 231 ± 127 nm. The aspect ratio for CNC-P and CNC-S are 11 and 13 respectively. The rheology properties like viscosity of CNC-S were compared to CNC-P in both matrices. The viscosity of the TPU/CNC-S and TPU/CNC-P solutions recorded highest value at 5 wt% of CNC loading similar result was recorded as well in water matrix. In TPU, at shear rate of 0.1 s−1, the viscosity of TPU/CNC-S is 192.1 Pa.S and TPU/CNC-P solution is 173.4 Pa.S. Meanwhile, in aqueous suspension, at shear rate of 0.1 s−1, the viscosity of CNC-P recorded higher value than CNC-S suspension at 772,800 Pa.S and 1045 Pa.S respectively. This has proven that type of acid in CNC production and suspension matrix influence the rheological properties of CNC suspension.

Efficient production of oligomeric chitin with narrow distributions of degree of polymerization using sonication-assisted phosphoric acid hydrolysis

A method of producing oligomeric chitin using sonication-assisted phosphoric acid hydrolysis was introduced. The processing was continuous and scalable. Oligomeric chitin fractions with narrow distributions of degree of polymerization were obtained by differential precipitation using ethanol as precipitating agent at different ethanol-to-phosphoric-acid-solution volume ratios. The yield of oligomeric chitin with degree of polymerization between 4 and 10 was ≈30% (mass fraction). The content of each fraction was characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI TOF MS). Changes in chemical composition of oligomeric chitin were negligible, as verified by MALDI TOF MS, Fourier-transform infrared, and nuclear magnetic resonance spectroscopy. This new method for producing oligomeric chitin molecules is rapid, cost-effective, and safe.

Micro- and nano-structures of cellulose from eggplant plant (Solanum melongena L) agricultural residue

Currently, agriculture sector produces enormous quantity of residues, creating severe environmental problems. These agricultural residues are rich in lignocellulosic fibers, making them sustainable sources to produce high added-value materials. This investigation aims to transform the eggplant plant residue (EPR) into purified cellulose microfibers (CMF) and cellulose nanocrystals (CNC). CMF with a yield of 54 %, diameter of 13.6 μm and crystallinity of 71 % were successfully obtained from raw EPR using alkali and bleaching treatments. By subjecting CMF to phosphoric and sulfuric acid hydrolysis, phosphorylated (P-CNC) and sulfated (S-CNC) were produced. P-CNC and S-CNC exhibited an aspect ratio of 89.4 and 74.2, zeta potential value of – 39.4 and – 28.7 mV, surface charge density of 116.7 and 218.2 mmol/kg cellulose and a crystallinity of 73 % and 80 %, respectively. Herein, the obtained cellulosic structures with excellent properties could be used in various applications, such as bio-derived fillers for polymer composites development.

Isolation and Characterization of Nanocrystalline Cellulose from Ramie Fibers via Phosphoric Acid Hydrolysis

ABSTRACT Nanocrystalline cellulose (NCC) was successfully isolated using cellulose extracted from ramie fibers via chemical pretreatments followed by phosphoric acid hydrolysis. The effects of acid concentrations and hydrolysis times on the characteristics of the NCC were investigated in this work. The obtained NCCs were characterized using Fourier infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). Fourier transform-infrared spectroscopy confirmed that hemicellulose and lignin were removed during the chemical pretreatments and hydrolysis. The results showed that the crystallinity index increased with increasing an acid concentration up to 16 M and then decreased drastically. The optimal acid concentration was found to be 16 M phosphoric acid at 150°C for 90 min during hydrolysis resulting in a rod-shaped NCC with a high crystallinity (89.28%), the average diameter (21.4 nm), and the average length (215.4 nm). The thermal stability was found to decrease with increasing acid concentration. The characteristic of NCCs was affected significantly by the acid concentration but not the hydrolysis time.

Kinetic and Thermodynamic Study of Corncob Hydrolysis in Phosphoric Acid with Low Yield of Bacterial Inhibitors

In this work, high sugar yield and low bacterial inhibitor production in dilute phosphoric acid hydrolysis of corncob is reported, with 54.3 g of sugar/100 g corn cob the highest yield observed at the most severe conditions with a degradation factor of only 0.03. Hydrolyses were obtained at different acid concentrations, temperatures and reaction times to analyse the effect of these variables on sugar production and degradation into bacterial inhibitors. The paper focuses on the kinetics and thermodynamics of corncob phosphoric acid hydrolysis, a topic scarcely studied. Kinetic constants calculated from either Saeman or first-order models allowed us to determine thermodynamic parameters and understand the energetic changes during hydrolysis. Sugar production has anactivation energy of 52 kJ mol−1 and sugar decomposition 78 and 115 kJ mol−1. Fourier Transform Infrared Spectroscopy analyses showed that sugar production came mainly from hemicellulose degradation.

Isolation of Thermally Stable Cellulose Nanocrystals from Spent Coffee Grounds via Phosphoric Acid Hydrolysis

Isolation of Thermally Stable Cellulose Nanocrystals from Spent Coffee Grounds via Phosphoric Acid Hydrolysis

Melt-Spun Nanocomposite Fibers Reinforced with Aligned Tunicate Nanocrystals.

The fabrication of nanocomposite films and fibers based on cellulose nanocrystals (P-tCNCs) and a thermoplastic polyurethane (PU) elastomer is reported. High-aspect-ratio P-tCNCs were isolated from tunicates using phosphoric acid hydrolysis, which is a process that affords nanocrystals displaying high thermal stability. Nanocomposites were produced by solvent casting (films) or melt-mixing in a twin-screw extruder and subsequent melt-spinning (fibers). The processing protocols were found to affect the orientation of both PU hard segments and the P-tCNCs within the PU matrix and therefore the mechanical properties. While the films were isotropic, both the polymer matrix and the P-tCNCs proved to be aligned along the fiber direction in the fibers, as shown using SAXS/WAXS, angle-dependent Raman spectroscopy, and birefringence analysis. Tensile tests reveal that fibers and films, at similar P-tCNC contents, display Young’s moduli and strain-at-break that are within the same order of magnitude, but the stress-at-break was found to be ten-times higher for fibers, conferring them a superior toughness over films.

Enhanced mechanical and hydrophobic properties of composite cassava starch films with stearic acid modified MCC (microcrystalline cellulose)/NCC (nanocellulose) as strength agent

The green composite cassava starch films were prepared using stearic acid modified microcrystalline cellulose (M-MCC)/nanocellulose (M-NCC) as strength agent, which shows good mechanical and hydrophobic properties and is a candidate for food package in this work. Microcrystalline cellulose (MCC) was prepared with 98% phosphoric acid hydrolysis and mechanical stirring at 600 r/min and nanocellulose (NCC) was prepared with 65% sulfuric acid hydrolysis. After using stearic acid to modify MCC and NCC, the casting method was used to prepare the M-MCC/cassava starch composite films and M-NCC/cassava starch films. Physical, mechanical, hydrophobic and thermal properties were characterized using SEM, electronic universal testing machine, contact angle meter and TGA. The results showed that: M-MCC and M-NCC can lead to the enhancement of mechanical and hydrophobic properties of composite films; 0.5% M-MCC and 1.5% M-NCC had the highest enhancement effect on mechanical properties, leading the tensile strength of cassava starch film increased by 484.5% and 327.7% respectively; As to hydrophobic property, when 2% M-MCC and 0.5% M-NCC added, the hydrophobicity of the film increased by 65.0% and 30.3% respectively. Overall, the enhancement effect of M-MCC was better than M-NCC. But when M-MCC/M-NCC was added, the thermal stability of films reduced.

Oil palm empty fruit bunch-based nanocellulose as a super-adsorbent for water remediation

Oil palm empty fruit bunch (EFB)-based nanocellulose (NC) was successfully produced as a super-adsorbent for water remediation via sulfuric (NCS) and phosphoric (NCP) acid hydrolysis and functionalized with activated carbon (AC). The formation of sulfonic groups on the NCS surface could achieve higher remediation capabilities than that of EFB-NCP. In a very short period, 2 wt.% of the formulated EFB-NCS super-adsorbent showed a selective and remarkable metal adsorption capability to Pb2+ at 86% efficiency and 24.94 mg/g adsorption capacity, which were double compared to those of rice-straw NC, and maintained a similar adsorptive capacity after second reusability. Conversely, the insignificant improvement in the adsorption capacity of NCS/AC was attributed to the disturbed surface functionality of micron-size AC. The NCS/AC showed notable organic degradation capability for reducing the chemical oxygen demand (COD) to 93%. All super-adsorbents could maintain the pH, TDS, sulfate and phosphate contents within the government water quality specifications.

Preparation of different polymorphs of cellulose from different acid hydrolysis medium.

In this study, medical cotton was subjected to acid hydrolysis in sulfuric, hydrochloric and phosphoric acid medium to prepare cellulose nanocrystals (CNC) with different morphologies and polymorphism. Morphology of the prepared CNC samples revealed fiber shaped morphology for sulfuric and hydrochloric acid hydrolyzed samples, whereas, spherical shaped for phosphoric acid hydrolyzed samples. The size of the spherical shaped CNC decreased with the increase of hydrolysis time, from 853 nm for 12 h to 187 nm for 48 h. X-ray Diffraction analysis showed that hydrochloric acid hydrolyzed CNC is cellulose I (CI), phosphoric acid hydrolyzed CNC is cellulose II (CII) and sulfuric acid hydrolyzed CNC contain both CI and CII. The crystallinity of sulfuric and hydrochloric acid hydrolysis samples was 91%, whereas, the crystallinity of phosphoric acid hydrolysis samples was between 43 and 60% depending on hydrolysis time. Thermal properties were also affected by the hydrolysis medium. Thus cellulose nanocrystals were prepared with different morphologies and physical characteristics through a facile method.

Production of cellulose nano-crystals from bacterial fermentation

The increasing studies of cellulose nano-crystals (CNCs) have proven its growing interest and demand to our society nowadays. However, the major production of CNCs from plant cellulose (PC) is considered less practical due to consuming more energy, time and cost in the purification process. Therefore, an optimum yield of CNCs from bacterial cellulose (BC) is a good alternative to fulfil the need. This study intended to investigate the optimum production of bacterial cellulose nano-crystals (BCNC) through phosphoric acid hydrolysis using One Factor at Time (OFAT) approach and compare its characteristics with plant cellulose. Acetobacter xylinum was incubated in Hestrin Schramm medium at 30°C and pH 6 in static culture. Chemical pre-treatment using sodium hydroxide was done later to prepare CNCs. The optimal conditions for phosphoric acid hydrolysis were BC: acid ratio of 100:1 at 35°C for 60mins. The characteristics and properties of BCNC were investigated and compared with PCNC produced from the same conditions. The result showed that the water holding capacity of BCNC was 5.31g water/g sample which was doubled of PCNC. Fourier-Transform Infra-Red analysis examined the absorption peaks of BCNC were at 1640cm-1 and 3400cm-1 which were similar to PCNC. Yet the crystallinity ratio of BCNC was comparable with PCNC at 0.78. Thermogravimetric analysis showed the degradation temperature of BCNC was 320.43°C, much higher than PCNC that degraded at 163.63°C. Observation from derivative thermo-gravimetric curves showed the ash content of BCNC was approximately 1.6% lower than PCNC, showing that BCNC exhibited much more purity than PCNC. It can be concluded that the behavior of BCNC was similar or even better than PCNC thus it was more advantageous to produce CNCs from bacterial fermentation rather than exploiting the plant source.

New approach for the determination of ortho-phenylphenol exposure by measurement of sulfate and glucuronide conjugates in urine using liquid chromatography-tandem mass spectrometry.

Ortho-phenylphenol (OPP) has been widely used as a fungicide and preservative. Although low-dose studies have demonstrated its low toxicity in animals and humans, high-dose exposure to this contaminant has toxic effects that range from skin irritation to bladder cancer. Thus far, monitoring of OPP exposure in the general population has been performed by measuring OPP after urine hydrolysis with the β-glucuronidase/arylsulfatase enzyme and sometimes by the use of a mineral acid. We developed a sensitive, accurate, and robust method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to specifically measure two-phase II OPP metabolites excreted in human urine, OPP sulfate (OPP-S), and OPP glucuronide (OPP-G). Comparative analysis of urine samples from 50 volunteers living in the Quebec City area using a direct method and phosphoric acid hydrolysis method previously developed in our laboratory showed no statistically significant difference (p value for paired t test = 0.701) in OPP concentrations. Moreover, a significant difference showed that underestimation (p value for paired t test = 0.025) occurs when β-glucuronidase/arylsulfatase enzyme deconjugation is used. The LOD achieved by the direct method permits the detection of OPP-S and OPP-G metabolites in urine at the submicrogram per liter level. Graphical abstract ᅟ.