Development of Mg-Al LDH and LDO as novel protective materials for deacidification of paper-based relics

Acidification of paper-based relics is a common problem,leading to their degradation and eventual loss.Paper deacidification is highly dependent on a limited variety of alkaline materials,and the development of new materials that are safe,efficient and easy-to-prepare is highly demanded to ensure a high level of safety and effective protection of paper-based relic.This study proposes the introduction of layered double hydroxide(LDH)and its calcined product,mixed metal oxide(layered double oxide(LDO)),as innovative protective materials for the deacidification of paper with varying levels of acidity.The results demonstrate that treatment with Mg-Al LDH/LDO can effectively modify the p H of acidic paper(e.g.,pH~4.0–6.4)to a neutral or weakly basic state,maintaining this desirable p H range even under long-term accelerated aging condition.Remarkably,LDH proves to be well-suited for the protection of slightly acidified paper(e.g.,pH>5.5),while LDO serves as an especially option for the deacidification of severely acidified paper(e.g.,pH≤5.5).During aqueous deacidification,due to the memory effect of the LDH-based materials,LDO is converted to rehydrated LDH,which creates a mild and appropriate alkaline retention in the paper,avoiding damage caused by strong alkalinity such as cellulose degradation and pigment fading during subsequent long-term natural preservation of the paper.Furthermore,Mg-Al LDH/LDO materials also exhibit flame-retardant and bacteriostatic properties.This opens up opportunities for the safe,efficient and multifunctional protection of acidified paper-based relics.

Chemical Investigation of Potassium Methyl Siliconate as Deacidification and Strengthening Agent for Preservation of Aged Papers

Potassium methyl siliconate （PMS） was investigated as a simple physicochemical modification in aged paper using silane coupling technique. The PMS-based solution was shown to favor penetration in the cellulose fibers on the paper with suitable uptakes being achieved at low concentrations. The studies of the physicochemical properties of the treated paper （mechanical strength and alkalinity） demonstrated that, besides the required deacidification feature and high level of alkali reserves, the immersion treatment by PMS allowed the enhancement of the mechanical intensities of paper arising from the interaction between Si--OH generated in hydrolysis of PMS and C--OH of cellulose on the paper. Adding ethanol into PMS solution could significantly improve mechanical properties of the aged paper treated by the formula apart from modifying the flatness of the paper. Optimized treatment process was achieved by altering the ratio of ethanol to water in PMS-based solutions. Contact angle measurements indicated the occurrence of hydrophobic character of the papers in immersion treatment with PMS-based solutions. The easy availability of the materials and simplicity of the method rendered it convenient for treatment for aged paper documents.

Isolation of a novel characterized Issatchenkia terricola from red raspberry fruits on the degradation of citric acid and enrichment of flavonoid and volatile profiles in fermented red raspberry juice

High content of citric acid in red raspberry juice leads to poor sensory experience. This study developed a feasible method to degrade citric acid in red raspberry juice using a novel characterized Issatchenkia terricola WJL-G4 isolated from red raspberry fruits. I. terricola WJL-G4 exhibited a potent capability of reducing the citric acid contents from(22.8 ± 0.08) g/L to(6.2 ± 0.02) g/L within 36 h fermentation, then completely depleted after 48 h. Furthermore, the contents of phenolic compound, including neochlorogenic acid, p-coumaric acid, raspberry ketone, and rutin significantly increased after 36 h fermentation. Fermentation increased total flavonoid contents in red raspberry juice, compared to that in control group. Volatile profiles exhibited to be enriched after fermentation, which contributed to the improvement of the juice taste. Our findings showed that I. terricola WJL-G4 can be applied in deacidification, enrichment of flavonoid compounds and volatile profiles in fermented red raspberry juice..

Study on Removal of Naphthenic Acids from White Oil by[BMIM]Br-AlCl_3

The removal of acid compounds （naphthenates） from acidic oil with ionic liquids was systematically investigated. [BMIM]Br-AlCl3 was used to investigate the effect on deacidification of oil. Experimental results showed that at a temperature of 323K with a molar ratio of AlCl3 to [BM1M]Br-AlCl3 of 0.2, and a mass ratio of IL to white oil of 4%, the deacidification rate could reach 75.9%. And a reaction time of 4 h was sufficient to achieve the goal. The study on reproducibility of catalytic performance of [BMIM]Br-AlCl3 showed the possibility of using the ionic liquid in the continuous catalytic reaction.

Performance Assessment of Nanocellulose Hydroxypropyl Methyl Cellulose Composite on Role of Nano-CaCO_(3) for the Preservation of Paper Documents

Deacidification and self-cleaning are important for the preservation of paper documents.In this study,nano-CaCO_(3) was used as a deacidification agent and stabilized by nanocellulose(CNC)and hydroxypropyl methylcellulose(HPMC)to form a uniform dispersion.Followed by polydimethylsiloxane(PDMS)treatment and chemical vapor deposition(CVD)of methyltrimethoxysilane(MTMS),a hydrophobic coating was constructed for self-cleaning purposes.The pH value of the treated paper was approximately 8.20,and the static contact angle was as high as 152.29°.Compared to the untreated paper,the tensile strength of the treated paper increased by 12.6%.This treatment method endows the paper with a good deacidification effect and self-cleaning property,which are beneficial for its long-term preservation.

Study on Laboratory Method for Refining of SR Diesel Fuel

The method for refining the straight-run diesel fuel was studied in laboratory scale in order to make the acid number of diesel fraction comply with the standard while removing the naphthenic acids contained in diesel without causing environmental pollution. After comparing the effect of refining using three solvents, the isopropyl alcohol-HOA was specified as the best solvent. Meanwhile, the relationship between the acid number of diesel fraction and the amount of solvent used and the relationship between the concentration of solvent and temperature and the stability of diesel in terms of its acid number were also investigated. Experimental results had shown that when the mass fraction of the HOA-IPA solvent was 20% at a dosage of 17 mL of the solvent and a temperature of 30℃, the acid number of the refined diesel fraction was 0.015 mg KOH/g with a good stability of acidity in the diesel fraction.

Adsorption behavior of free fatty acids and micro-components in rapeseed oil on alkaline microcrystalline cellulose

Alkaline microcrystalline cellulose (AMC) was used as adsorption agent in deacidification in this paper. Changes of isothermal adsorption of free fatty acids (FFA) and micro-components (α-tocopherol and β-sitosterol) in rapeseed oil on AMC were investigated. The results showed that difference in initial micro-component contents would not change adsorption characteristics of AMC to FFA. Adsorption characteristics were always as the following: Langmuir equation was more suitable to static adsorption process of AMC to FFA than Freundlich equation; moderate temperature (30-40oC) was advantageous to adsorption; adsorption was a preferential one. The highest retention rate of α-tocopherol and β-sitosterol during absorptive deacidification by AMC were 99.5% and 91.5% respectively. Therefore, AMC was suitable for adsorption deacidification application of rapeseed oil.

Nanocomposites composed of modified natural polymer and inorganic nanomaterial for safe,high-efficiency,multifunctional protection of paper-based relics

Paper-based relics as important carriers of human history and civilization have been facing severe damage problems,and their protection is a major project for cultural heritage restoration.So far,safe,high-efficiency,and multifunctional protection materials are still urgent to be developed.Herein,through screening a series of alkaline nano-oxides and cleverly combining the advantages of modified natural polymer(quaternized chitosan)and inorganic nanomaterials(Zn O),we successfully prepared their functional nanocomposites with multiple properties and pioneered their smart application for multifunctional protection of paper relics.By spraying loads,this kind of nanocomposites can effectively and safely inhibit the acid degradation of paper relics and long-term maintain a natural or weak basic state even under harsh accelerated aging conditions.Meanwhile,the coating of nanocomposites does not change the chromatic aberration but partially improves the hydrophobicity.Moreover,the mechanical properties of paper relics are reinforced up to more than one time for all-around tensile strength,folding endurance,and tearing strength.It is worth noting that the usage of nanocomposites can avoid the discoloration or fading of p H-sensitive pigments/dyes and prevent the blue/red inks from ink-spreading.By integrating the anti-microorganism effects of the two components,the nanocomposites have exhibited a broad antimicrobial capacity for both fungi(e.g.,Plectosphaerella cucumerina and Aspergillus unguis)and bacteria(e.g.,Staphylococcus aureus).The acquired knowledge not only represents an advanced step for designing functionalized inorganic/polymer nanocomposite but also sheds light on the multi-functional integrated protection of paperbased relics.