Drying Stress and Strain in Tension Wood: A Conventional Kiln Schedule to Efficiently Dry Mixed Tension/Normal Wood Boards in Poplar

Orthotropic drying stresses of tension and normal wood in poplar were evaluated. The degree of residual stresses was interpreted by prong and slice cutting tests. A strain gauge was employed to determine longitudinal drying stresses. Mixed tension/normal wood boards were also dried using three different schedules, T₈ F₄, T₈ F₅, and T₉ F₄ to find the best schedule. Results revealed more intense drying stress in the longitudinal and radial directions of tension wood. Despite a high susceptibility of the mixed tension/normal wood boards to drying defects, the quality of the boards dried by the schedule of T₉ F₄ was satisfactory.     

Kinetics and thermodynamic studies of Cr(VI) adsorption using environmental friendly multifunctional zeolites synthesized from coal fly ash under mild conditions

Abstract

The Na-P1 zeolite was produced from coal fly ash and modified with different environmental friendly surfactants. The potential of these green modified zeolites was investigated as adsorbents for Cr(VI) ions in a batch system. XRD, SEM, XRF, and ICP-AES analyses were used for the characterization of raw materials and zeolite samples. The environmental friendly modified zeolites successfully immobilized different toxic elements in their framework inhibiting the transfer of these toxic elements to the surrounding liquid phase. The effects of various operational parameters on Cr(VI) removal were studied. The Hexamethylenediamine (HDTMA) and Ammonyx KP (KP) modified zeolites had larger chromium removal potential than the other samples at all temperatures. The effectiveness of Cr(VI) ions elimination became greater as the pH decreased and the adsorbent dose increased. The Freundlich, Langmuir, and Dubinin–Radushkevich isotherms were fitted to the equilibrium data. The Dubinin–Radushkevich and Langmuir models gave a better fitness to equilibrium data of HDTMA-Na-P1 and KP-Na-P1, respectively. The positive and high ΔH° values showed the endothermic nature of the total Cr(VI) sorption procedure and indicated that Cr(VI) adsorption onto HDTMA-Na-P1 and KP-Na-P1 is a chemisorption. The negative ΔS° values also showed that chromium ions were stable on the surface of adsorbents. The adsorption potential of the developed eco-friendly KP-Na-P1 was higher than those of other adsorbents reported in the literature.     

Bioactive compounds and advanced processing technology: Phaleria macrocarpa (sheff.) Boerl,a review

Recent technological advances and the development of new methods has provided an opportunity to obtain highly purified natural bioactive compound extracts with potential for the treatment and prevention of human diseases. The use of hazardous and toxic solvents for the extraction and processing of bioactive compounds from plant materials is considered a problem for health, safety and environmental pollution. Advanced technology aims to increase production of the desired compounds and find an alternative to using toxic solvents in the extraction of bioactive compounds from plant materials. The ever growing interest in plant bioactive compounds and today's concerns about environment issues have led to an increased need for an efficient and green extraction method. This review is focused on the extraction of bioactive compounds from plants using advanced and environment‐friendly methods such as supercritical fluid extraction, microwave‐assisted extraction, ultrasound‐assisted extraction and similar techniques that can extract rapidly and free from organic residues. An updated overview of the bioactive compounds present in the plant Phaleria macrocarpa and its extraction, fractionation, purification and isolation is provided. The advantages and disadvantages of both conventional and non‐conventional extraction methods are also discussed in this review. © 2014 Society of Chemical Industry     

Mechanochemical Synthesis of CPM‐5: A Green Method

The development of green technologies for the manufacture of various materials is considered as one of the approaches to address some of the environmental issues of commercializing new materials. A mechanochemical (MC) method is developed to synthesize crystalline porous material‐5 (CPM‐5). The effect of different mechanical parameters, including oscillation frequency and time and the number of metal balls used for milling is studied. Results revealed that CPM‐5 crystals are successfully formed under optimized conditions. It was noted that the thermal treatment of the samples after grinding is very crucial for the formation of CPM‐5 under the studied conditions. Moreover, washing of samples with a 1:1 solution of dimethylformamide (DMF):H₂O remarkably enhanced the surface area of the final product.