Research Articles

A bioadsorbent with a high specific surface area and high content of oxygen-containing functional groups was prepared from silica depleted rice straw ash (SDRSA). The starting material was a by-product of rice straw after alkoxysilane extraction. The maximum adsorption capacity of SDRSA for copper ions was 26.7 mg/g, which was higher than previously reported biomass adsorbents. The effects of adsorbent dose, pH, contact time, and other conditions on the adsorption performance of SDRSA on Cu²⁺ were investigated. The adsorption process of Cu²⁺ on SDRSA was well fitted by the Langmuir isotherm model and the pseudo-second-order kinetic model. The physicochemical properties and adsorption mechanism of SDRSA were investigated by specific surface area testing (BET), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Boehm titration methods. Electrostatic interaction, complexation, ion exchange, and precipitation are the possible Cu²⁺ removal mechanisms. The preparation method requires only simple washing and drying, and the alcohol can be distilled and recycled. Thus, SDRSA is very low cost and convenient to prepare in large quantities. This work presents a novel approach to optimize adsorbent production to mitigate heavy metal pollution.

Fast-growing poplar (Populus tomentosa Carr) can produce wood veneers, but their poor quality restricts their application in construction and building. Modification of wood has the potential to improve its properties. In this study, poplar veneers were impregnated with calcium carbonate (CaCO₃) to reinforce their performance. The results showed that CaCO₃ was uniformly distributed in cell lumens in impregnated veneers. After impregnation, the maximum weight gain rate was up to 41.4%, and water uptake decreased from 6.82% to 0.94%. The hardness increased from 7.6 to 10.0 MPa, and the extent of wear fell from 0.91% to 0.05%. The ignition time was prolonged, and the heat release rate and total heat release were low. Experimental results demonstrated that CaCO₃ improved the physical-mechanical properties and flame retardancy of poplar veneers.

Cashew apple bagasse is biomass rich in little-exploited lignocellulosic material. This study used this biomass as a support for cell immobilisation of Saccharomyces cerevisiae. For this purpose, the immobilisation technique by attachment to a surface was applied. The bagasse used in this study contained 32.6% lignin. After delignification, the lignin content of the bagasse was 3.33%. The cell density was 1.21 × 10⁸ cells g^-1 for the immobilised cells prepared for 24 h. For the immobilised cells prepared for 48 h, the cell density was 1.71 × 10⁸ cells g^-1. Microscopic observations showed that the adhesion of the yeast cells to the surface of the support occurred on all layers with the cells immobilised for 48 h. These results highlight the efficiency of cell immobilisation of S. cerevisiae on cashew apple bagasse.

Wooden columns, as an important load-bearing wooden component of traditional wooden structures, determine the safety of an entire building. With the increase in material deterioration, the overall health and life of ancient buildings is affected. In this study, the deterioration of wooden columns of ancient buildings in the central axis of the Nanyang Fuya Museum was detected through a combination of macroscopic visual inspection and moisture content testing. The result was that the deterioration degrees and MCs of wooden columns located in the south direction, with good ventilation effect or with oil paint protection were lower than those of wooden columns located in the north direction, with poor ventilation effect or without oil paint protection. The deterioration degree increased with the increase of MC. The results of this research provide the basis for the analysis of the causes and risks of material deterioration.

The most suitable generative production method was selected in this work by applying different treatments to endemic Centaurea olympica seeds. The development performance and adaptation ability of the species in natural and cultural conditions (in the natural population, in pots and in the garden) were determined, with the goal to protect the species under ex situ conservation. The growth performance of the plant was monitored, and its ornamental plant potential was evaluated. The obtained data were compared with the data from the natural population. All morphological and phenological observations showed that the species can easily adapt to cultural conditions. For 2 months in the summer period, it is a lilac-flowered herbaceous plant that can be preferred for gardens with increasing number of shoots and flowers in parallel with its development. Among the different pretreatments applied to the seeds of the species, the highest germination percentage (73.5%) and germination speed (T₅₀=8 days) was found with 600 ppm GA₃ treatment for 24 h after cold-wet stratification at 4 °C for 3 months. The appropriate germination temperature was determined as 20 °C.

Indoor environmental quality has a profound effect on human health and productivity. In this respect, this study evaluates indoor air quality in terms of its various parameters in sustainably built homes in three different locations. A supplementary study to examine the formaldehyde emission levels from furniture with three different finishes was also undertaken. A questionnaire-based survey was then conducted to evaluate the general public perception of the prevailing indoor air quality in the three locations. The results revealed that temperature, relative humidity, indoor air speed, particulate matter (PM10), CO₂, NO₂, and total volatile organic compounds (TVOC) and formaldehyde (HCHO) readings were not significantly different between the three locations and were below the existing limit allowed for indoor environmental quality. However, the HCHO emission was the highest from furniture with the two-layer coatings, followed by single layer coating, and finally the furniture with the veneer overlay. It was noteworthy that the general public’s awareness and knowledge of indoor air quality was relatively poor, except for the tertiary level educated respondents. In this regard, policymakers need to increase the awareness and knowledge of indoor environmental quality among the general public, if non-compliance is to be detected and promptly addressed.

The most promising alternative to the methyl bromide fumigation of exported logs is steam-heating the log in a vacuum. Research has confirmed that steam heating to 56 °C for 30 minutes kills all viable propagules of oak wilt pathogen (Bretziella fagacearum) in the sapwood of oak logs. The purpose of this study was to determine whether this heat-treatment method has any effect on the quality or value of white oak veneer logs shipped between the US and EU. Seventeen steam- and vacuum-treated and seventeen untreated control logs were shipped from Baltimore, Maryland to the Czech Republic, for processing into veneer, between December 2021 and February 2022. The treated and untreated logs were sawn into flitches, soaked in hot water vats, sliced, dried, and the veneer from each log was graded for quality. Each log was assigned a value based on the veneer quality and yield. The average value of treated log was 1,547 €/m³, and the average value of the untreated logs was 1,539 €/m³. The null hypothesis was statistically confirmed. Therefore, it is concluded that the 56 °C/30 min, sapwood heat treatment using vacuum and saturated steam had no adverse impact on the value of the white oak veneer logs.

High-frequency electromagnetic fields refer to electromagnetic waves with frequencies ranging from 100 kHz to 300 MHz. High-frequency medium heating has the advantages of uniform heating, rapid energy consumption, and environmental protection. While it has a wide range of applications, the use of high-frequency dielectric heating in the bamboo industry is rare. Understanding the influence of bamboo temperature rise rate in high-frequency heating could promote bamboo industry development. In this work, curved bamboo was tested with high-temperature energy for continuous heating. The influence of moisture content of bamboo, sample thickness, and high-frequency processing power on temperature rise rate were studied. The results showed that the water content of bamboo affected the temperature rise rate. The effect of high-frequency heating was highest when the moisture content of bamboo was close to 11%. The thickness of sample had little effect on the temperature rise rate, but the high-frequency power had a significant effect on the temperature rise rate. The temperature rise rate of the lower and higher frequency power levels increased slowly and was close to constant. The heating power was 11 kW, and the temperature rise rate was the highest.

To address the challenges associated with corn stover utilization and the synthesis of phenyl- and methacryloyloxy-based silsesquioxanes (SQs) with difficulty and poor controllability, the authors present a novel approach that combines advanced biorefining techniques and innovative chemical synthesis methods. Spirocyclic alkoxysilane synthesized from corn stover ash was subsequently utilized for the synthesis of phenylSQs. The resulting phenylSQs were then subjected to fluorine ion-catalyzed rearrangement with 3-(trimethoxysilyl)propyl methacrylate (KH570) to yield SQs containing phenyl and methacryloyloxy functional groups. Through manipulating the ratio of phenylSQs and KH570, the authors successfully achieved a desired ratio of functional groups on individual SQ cages. Optimization of the ratio significantly impacted product collection, with a range of 5.5:1 to 8.5:1 recommended for efficient and effective synthesis. This study represents an important advancement in the field of high-value conversion of biomass, offering an easy means of tailoring the structure of phenyl- and methacryloyloxy-based cage SQs.

A separable glued-laminated timber (GLT, Larix kaempferi Carr.)-steel beam system is presented in this work for easy recycling at the time of disposal. The minimum thickness of steel required to induce compressive GLT failure was assembled with GLT by inclined screws. In a total of 8 GLTs, 3 GLTs were not reinforced (control group), and 5 GLTs were reinforced with steel plates (comparison group). In the GLT in the comparison group, a steel plate (SPHC, yield strength: 227 MPa, modulus of elasticity 166.33 GPa) was installed with screws (∅9x160mm, 45°). The deflection and load of specimens were measured by a third-point bending test to derive their bending stiffness and load-carrying capacities. All specimens in the control group showed brittle tensile failure, but all specimens in the comparison group showed ductile behavior and maintained a load-carrying capacity of about 30 kN. After the compression failure of the GLT, there was no damage to the screw connection, while the steel plate was extended. Based on the behavior of the steel, a GLT-steel beam prediction model was developed, similar to the structural design method for reinforced concrete.