For the first time, the expansion grade of graphite was studied through the effect of the flake size. The result shown the larger flake size exhibits a higher expansion grade. In addition, the more expanded material, the higher specific surface area can be obtained. The synthesized expanded graphites were used for the adsorption of methylene blue. The expanded graphite with the highest expansion grade displayed the highest adsorption capacity due to its specific surface area.
Lĩnh vực giáo dục Khoa học Tự nhiên (KHTN) có ưu thế hình thành và phát triển cho học sinh các phẩm chất như tự tin, trung thực; các năng lực tìm hiểu và khám phá thế giới tự nhiên qua quan sát và thực nghiệm; năng lực vận dụng tổng hợp kiến thức khoa học để giải quyết vấn đề trong cuộc sống, ứng xử với tự nhiên phù hợp với yêu cầu phát triển bền vững xã hội và môi trường. Bài viết sau đây đề cập đến việc bồi dưỡng cho giáo viên năng lực tìm hiểu thế giới tự nhiên thông qua cách tổ chức các hoạt động khám phá và bảo vệ môi trường, nhằm đáp ứng được những yêu cầu của dạy học môn KHTN trong chương trình trường trung học cơ sở (THCS).
In this paper, nanocomposite materials of xCoFe2O4/(1-x)(TiO2–5%La) (x = 0.2) were synthesized in a two-step procedure, combining a co-precipitation and hydrothermal methods. The morphological and structural characteristics of the material were studied through XRD, SEM, EDS, BET measurements. The materials showed the high adsorption capacity for a organic dye - Congo Red (CGR) . The adsorption efficiency reaches 99.34% after 10 minutes of treatment process, with the amount of adsorbent used is 0.04g /100ml of solution of 32 µmol/l CGR.
Tourism development plays a crucial role in creating employment, boosting the revenue of the economy, supporting to improve the living standard. While tourism provides many opportunities to improve the well-being of local communities, the expansion of tourism needs to be effectively managed to avoid the degradation of natural capital. Assessing resource awareness and use behavior is an effective way to determine the public’s commitment to natural resource conservation and restoration in protected areas. The research was performed in Bach Long Vy Island (BLVI) in Hai Phong city, Viet Nam which is the first National Marine protected area designated by the Vietnamese Government. The aim of this study was to estimate tourists’ Willingness to pay (WTP) for natural resource conservation at BLVI through using Contingent valuation method (CVM) with the single-bounded dichotomous choice technique and the random utility model. We estimate the average visitor WTP is VND 153 370 per year (approx. US$6.58), while the aggregate WTP of tourists for the environmental conservation is VND 7.67 million per year (approx. US$32 900) (currency conversions taken as the average rate in September 2020; US$1 to VND 23280). The calculated results show that income and gender factors have significant effects visitors WTP whereas age and education have opposite effects. The outcomes of this research demonstrate the potential tourism value of this island due to the natural amenities and high biodiversity, particularly originating from its marine ecosystems. This result provides valuable scientific information for decision makers and local authorities and should be useful in establishing strategies to prevent the deterioration of ecosystems at BLVI (e.g., an environmental charge or entrance fee), thus contributing to sustainable tourism development.
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