Preparation of a hydrophobic recycled jute-based nonwoven using a titanium dioxide/stearic acid coating

This work aims at developing a hydrophobic treatment for jute fiber-based nonwovens. Three solutions of titanium dioxide (TiO₂) nanoparticles were prepared through a sol–gel method by varying the molar ratio of the various constituents. The nonwoven was pretreated with these solutions before being impregnated with different concentrations of stearic acid. The TiO₂ nanoparticles synthesized are amorphous; their size varies with the concentration of ethanol used as a solvent in the sol–gel method. The nanoparticle coating produced on the jute fibers is uniform. The nonwoven wettability was evaluated by measuring its water contact angle and retention time; the nonwoven became hydrophobic at the lowest fatty acid concentration tested. An increase in the stability of the hydrophobicity was observed when the TiO₂ nanoparticle pretreatment was used compared to the application of the stearic acid treatment only. No detrimental effect of the hydrophobic treatment on the nonwoven mechanical performance and thermal stability was observed. These results demonstrate the potential of the TiO₂ nanoparticle/stearic acid treatment as a fast method to provide a stable hydrophobicity to recycled jute-based nonwovens.     

Evaluation on some finishing properties of oil palm plywood

Oil palm is the largest and most important plantation crop in Malaysia. The oil palm generally lasts for 25–30 years before the next replantation is done. Substantial amount of biomass in the form of palm trunk results from plantation cycle. This resource is simply left on the ground to decay and is not used as raw material to manufacture any kind of value-added products. The objective of this study was to investigate the possibility of manufacturing plywood from oil palm trunks and to evaluate some of the finishing properties of such experimental panels in comparison to those from Shorea sp as control samples. Three-ply plywood samples were produced from 5 mm thick veneers of oil palm using urea formaldehyde adhesive. Three types of chemicals, namely nitrocellulose, pre-catalyzed lacquer and polyurethane were used to finish experimental panels. The surface finished with nitrocellulose had the lowest contact angle on raw surface of oil palm plywood and wood. The average cross cut tape index of oil palm plywood was comparable to Shorea sp. All finishing materials of oil palm plywood produced impact rating of 4 except for surface finished with nitrocellulose while finishing on wood indicated an impact rating of 3. Oil palm plywood had higher weight loss compared to Shorea sp. Based on results from contact angle, cross cut tape index, impact rate test, weathering, and soil burial test methods it appears that the samples showed acceptable finishing properties comparable to those of solid wood.     

Antioxidant constituents from Lawsonia inermis leaves: Isolation,structure elucidation and antioxidative capacity

The antioxidant potential of different fractions of Lawsonia inermis (Lythraceae) was investigated. The n-butanolic fraction showed the highest yield of extraction; it also exhibited a strong antioxidant activity in the DPPH assay and a potent capacity in preventing linoleic acid oxidation. Five phenolic glycosides were identified in this fraction. The structure of a new compound was established as 1,2,4-trihydroxynaphthalene-1-Ο-β-d-glucopyranoside. In addition, the known 2,4,6-trihydroxyacetophenone-2-Ο-β-d-glucopyranoside was described for the first time in this species. The three other compounds, lalioside (2,3,4,6-tetrahydroxyacetophenone-2-Ο-β-d-glucopyranoside), lawsoniaside (1,2,4-trihydroxynaphthalene-1,4-di-Ο-β-d-glucopyranoside) and luteolin-7-Ο-β-d-glucopyranoside, have been previously reported in L. inermis. The antioxidant activity of these glycosides was evaluated by DPPH and β-carotene assays, and compared to those of commercial standards. 1,2,4-Trihydroxynaphthalene-1-Ο-β-d-glucopyranoside was the most active in the DPPH free-radical scavenging test (EC₅₀ = 6.5 μg/ml) and showed a moderate inhibition in the β-carotene bleaching assay. Chemical components of L. inermis have good antioxidant capacities and this species could be used as a potential source of new natural antioxidants.     

Aerobic and Anaerobic Bacterial and Fungal Degradation of Pyrene: Mechanism Pathway Including Biochemical Reaction and Catabolic Genes

Microbial biodegradation is one of the acceptable technologies to remediate and control the pollution by polycyclic aromatic hydrocarbon (PAH). Several bacteria, fungi, and cyanobacteria strains have been isolated and used for bioremediation purpose. This review paper is intended to provide key information on the various steps and actors involved in the bacterial and fungal aerobic and anaerobic degradation of pyrene, a high molecular weight PAH, including catabolic genes and enzymes, in order to expand our understanding on pyrene degradation. The aerobic degradation pathway by Mycobacterium vanbaalenii PRY-1 and Mycobactetrium sp. KMS and the anaerobic one, by the facultative bacteria anaerobe Pseudomonas sp. JP1 and Klebsiella sp. LZ6 are reviewed and presented, to describe the complete and integrated degradation mechanism pathway of pyrene. The different microbial strains with the ability to degrade pyrene are listed, and the degradation of pyrene by consortium is also discussed. The future studies on the anaerobic degradation of pyrene would be a great initiative to understand and address the degradation mechanism pathway, since, although some strains are identified to degrade pyrene in reduced or total absence of oxygen, the degradation pathway of more than 90% remains unclear and incomplete. Additionally, the present review recommends the use of the combination of various strains of anaerobic fungi and a fungi consortium and anaerobic bacteria to achieve maximum efficiency of the pyrene biodegradation mechanism.