Research Articles

Poplar pretreated by steam explosion was used as an adsorbent to simulate the adsorption process of nickel ion in wastewater. The result of kinetics suggested that the pseudo-second-order model was well suited to describing the adsorption of nickel ion. Through controlled adsorption, steam-exploded poplar was recycled after Ni2+ adsorption and then reduced to carbon-supported nickel catalyst (NiC700). Spectrum analyses of Fourier transform infrared spectrometry (FTIR), X-ray diffractometry (XRD), X-ray photoelectron spectrometry (XPS), Brunauer Emmett-Teller (BET) surface area, and electrochemical tests were applied to study the properties of the NiC700 relative to the control carbonized materials having no Ni (C700). The FTIR analysis revealed that there were chemical interactions and ion changes between OH, C–H, C=O, and heavy metal ions in the bio-adsorption process of nickel. The surface area of NiC700 was 1480 m2/g. The presence of Ni nanoparticles in NiC700 after reduction was confirmed by the XRD and XPS analyses. Electrochemical impedance spectroscopy (EIS), photocurrent (IT), and Mott Schottky curve results revealed that the conduction band potential of NiC700 (ECB, NiC700) was -0.10 eV vs. RHE (reversible hydrogen electrode) as an n-type semiconductor, and the Ni-doped carbon fiber exhibited certain electrophotocatalytic activity due to the nickel modification.

The mechanism of lignin degradation via white rot fungi was studied. Phanerochaete chrysosporium and Pleurotus ostreatus were used for all the experiments, i.e., measuring the concentration and structure of alkali lignins and studying the effect of the substrate concentration and enzyme activity on the removal. Gas chromatography-mass spectrometry was performed on the reaction liquid of the lignin degradation enzyme system. Alkali lignin had a characteristic absorption spectrum with a peak at approximately 280 nm. Precipitation in the laccase (Lac) degradation system occurred earlier, as well as being more obvious than that in the manganese peroxidase (Mnp) degradation system. The maximum removal was 29.4% in the Mnp degradation system at a concentration of 40 mg/L. The removal increased in a concentration-dependent manner in the Lac degradation system. The increase in Mnp and Lac enzyme activity led to an increased alkali lignin removal. The removal of the control group was significantly lower than the experimental degradation systems. The degradation mainly produced organic acids, esters, and aromatic substances. In conclusion, white rot fungi could effectively remove alkali lignin, in which precipitation played a major role, followed by enzymolysis; the enzymolysis was associated with the alkali lignin concentration and enzyme activity.

Three types of phenolic acids (caffeic, ferulic, and chlorogenic acid) were identified and quantified in two halophytic plants (Salicornia bigelovii and Salicornia sinus-persica). Analysis was performed using a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) system via the standard addition method. The matrix effect (ME), recovery efficiency (RE), and process efficiency (PE) parameters were evaluated for S. bigelovii extracts, which revealed a strong ME on the ionization of the three acids. The matrix had little to no effect on the extraction step for all samples. The quantitation results revealed that S. bigelovii was more abundant in the acids analyzed (total of 319.2 µg/g dry water extract) when compared to S. sinus-persica (117.2 µg/g dry water extract), and chlorogenic acid was the dominant component. The extractives content was high in both plants, representing over 35% of the dry plant weight. All the extracts exhibited antioxidant activity toward both DPPH and ABTS radicals at levels comparable to other medicinal plants.

Extensive comparative characterization was performed to explore halophytes native to the Persian (Arabian) Gulf. Ten species collected from the Western region of Abu Dhabi, United Arab Emirates (UAE) were analyzed for their lignocellulosic components as well as for ash and extractives content. It was found that the species significantly differ in the content of carbohydrates, lignin, total ash-free extractives and total ash. The total ash content was found to negatively influence the content of carbohydrates. Based on the characteristics, it is concluded that Cornulaca aucheri is the most attractive as a source of carbohydrates, and Tetraena (Zygophyllum) qatarensis has the potential to produce the highest yield of the extractives fraction.

Enhancing the mechanical, thermal, and degradation properties of a poly(lactic acid) (PLA) blend without deteriorating its other useful features was the goal of this work. The isolation of cellulose nanocrystals (CNCs) from Agave angustifolia fibers was carried out, and the properties of the bio-nanocomposites comprising these CNCs were evaluated, which included PLA, natural rubber (NR), and liquid NR (LNR). Transmission electron microscopy and zeta potential analysis confirmed the successful isolation of CNCs from agave fibers after several chemical treatment steps. The effects of different CNC loadings on the properties of the bio-nanocomposites were investigated using tensile tests, thermal analysis, morphological analysis, and water absorption tests. Bio-nanocomposites containing 5 wt% and 7.5 wt% CNC had the optimal tensile modulus and strength, respectively. Different levels of CNC did not noticeably affect the thermal stability of the bio-nanocomposites, although the thermogram curves increased slightly as CNC content increased. The addition of CNC at different loadings affects the crystallization rate of PLA blend. The water absorption capacity increased as CNC level increased, and 5 wt% CNC gave rise to the highest water absorption. The four-component bio-nanocomposites created in this study provided an alternative for producing new green materials with tunable physical, mechanical, and thermal properties.

Edible coatings (EC) are a biodegradable alternative for food preservation. In this work EC based on extracellular compounds of Humphreya coffeata and pectin (PHC) were elaborated and characterized through testing on strawberries. Two PHC types were obtained (PHC1, which settled, and PHC2, which floated during the first separation). The conservation period of the strawberry and the phenol content and antioxidant activity in strawberries with the EC were determined. Four EC were prepared (EC1, EC2, EC3, and EC4), in which EC1 did not contain any PHC, EC2 contained PHC1, EC3 contained PHC2, and EC4 contained both PHCs. Three EC types (EC2, EC3, and EC4) delayed the decay of strawberries approximately 90% at 20 °C during the first 10 days of evaluation, and at 4 °C the effect was between 75 and 90% after 25 days of experimentation. However, EC3 and EC4, both of which contained PHC2, presented the best results. The content of total phenols (approximately 55 mg (gallic acid equivalent (GAE)/mL) and the free radical scavenging activity were 35% with ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and 75% with DPPH (2,2-diphenyl-1-picrylhydrazyl) in strawberries with EC. Thus, EC are an alternative for preserving strawberries without losing their antioxidant capacity.

Color changes were tested and compared for heat-treated Paulownia tomentosa and Pinus koraiensis wood treated with hot oil or hot air for further utilization of these species. Hot oil and hot air treatments were conducted at 180, 200, and 220 °C for 1, 2, and 3 h. Heat-treated wood color changes were determined using the CIE-Lab color system. Weight changes of the wood before and after heat treatment were also determined. The weight of the oil heat-treated wood increased considerably but it decreased in air heat-treated wood. The oil heat-treated samples showed a greater decrease in lightness (L*) than air heat-treated samples. A significant change in L* was observed in Paulownia tomentosa. The red/green chromaticity (a*) of both wood samples increased at 180 and 200 °C and slightly decreased at 220 °C. The yellow/blue chromaticity (b*) in both wood samples increased at 180 °C, but it rapidly decreased with increasing treatment durations at 200 and 220 °C. The overall color change (ΔE*) in both heat treatments increased with increasing temperature, being higher in Paulownia tomentosa than in Pinus koraiensis. In conclusion, oil heat treatment reduced treatment duration and was a more effective method than air heat treatment in improving wood color.

Entrepreneurs and small and medium enterprises are the foundation of the Malaysian furniture industry. Yet, in a multi-ethnic society such as Malaysia, the success factors of entrepreneurs and small and medium enterprises (SMEs) in the furniture industry have not been studied. Therefore, this study evaluated the success factors of entrepreneurs of the Malay and Chinese ethnic groups in the furniture industry and discerned the growth trajectory of young entrepreneurs from wood science and technology programs in the furniture industry. A questionnaire-based survey was used with the assistance of relevant trade associations and universities. The results were statistically analyzed to establish the significant differences between the two ethnic groups in their perceived success factors. The results revealed that Malay entrepreneurs pay more attention to political and socio-cultural factors to gain success, whereas Chinese entrepreneurs focus on enhancing their competitiveness to remain viable. Further, young graduates showed a reduced desire to pursue a career in the furniture industry, as they deem it not environmentally sustainable in addition to limited career growth. These results suggested that current entrepreneurship development programs may need to be revised, so as to assist in producing more resilient and successful entrepreneurs in the future in the furniture industry.

This study proposed action scenarios for urban solid waste management in six municipalities in the Corumbataí River Basin. The operating scenarios were designed for organic waste treatment and for the shared disposal of urban solid waste. Six municipalities were studied, five of which had less than 30,000 inhabitants (Analândia, Charqueada, Corumbataí, Ipeúna, and Santa Gertrudes). In addition, Rio Claro had 199,000 inhabitants. Thus, the transport and transshipment stages, general infrastructure, and final disposal in landfills were analyzed. Further, the three scenarios for organic waste treatment were conducted separately. The items and the cost of implementation were estimated for decentralized composting, centralized composting, and biomethanization of waste with electricity recovery. The biomethanization scenario included the commercialization of electricity, so it generated revenues that decreased costs. This cost reduction was especially notable in the last years of the project when the goals of diversion of organic waste through selective collection were higher. The results suggested that the investigated scenarios could improve organic waste treatment and that the biomethanization scenario with electricity generation presented lower average costs per inhabitant than the centralized and decentralized composting scenarios.

Effects of soaking aqueous ammonia pretreatment were considered for fast-growing poplar wood in the context of bioethanol production. The milled Populus trichocarpa wood with a particle size of 0.43 to 1.02 mm was pretreated at two temperatures (50 °C and 90 °C) and two concentrations of ammonia solution (15% and 20% w/w) for 20 h. The lignin content decreased by 46% in the biomass treated with the most severe conditions. After enzymatic hydrolysis, the sugar yield was analysed, and the results indicated that increased temperature and ammonia concentration during pretreatment resulted in higher glucose content. Additionally, changes in the degree of polymerization and available pore volume were investigated.