The paper deals with a comparative study of equilibrium and kinetics of phenol adsorption from aqueous solutions by means of commercial activated carbons and semi-cokes, differing in the nature of feedstock, production technology and structural characteristics. The main adsorption parameters are calculated with the usage of Langmuir and Dubinin–Radushkevich equations. The change in the characteristics of the structure and state of the surface of semi-coke P2 as a result of modification is estimated. It was found that phenol adsorption kinetics is described by a pseudo-second-order model. The adsorption rate constants and the coefficient of external diffusion mass transfer are calculated. It is proved that phenol extraction from aqueous solutions presents a mixed-diffusion nature, and the process rate is limited by external mass transfer for 13 min for SKD-515 and 22 min for ABG. To increase the adsorption capacity, the oxidative modification of the semi-coke P2 was carried out. Considering the economic and technological aspects, ABG semi-coke is recognized as a promising sorbent for phenol extraction from aqueous media.

This study was carried out to select the suitable and high leaf yielding broadleaf mustard genotypes for the mid-hill conditions of Nepal. We evaluated seven germplasms of broadleaf mustard (Brassica juncea var. rugosa (L.) Czern.) namely, ‘HRDBLM001’, ‘HRDBLM004’, ‘HRDBLM007’, ‘HRDBLM009’, ‘HRDBLM010’, ‘Marpha Chauda Pat’, and ‘Khumal Chauda Pat’ in the field of the National Horticulture Research Centre, Khumaltar under Nepal Agricultural Research Council during the winter season of two consecutive years, 2019 and 2020. The germplasms were collected from the local diversity centres in the country. The experiment was laid out in the Randomized Complete Block Design (RCBD) in three replications per treatment. Seeding was done in September, and 28-day-old seedlings were transplanted in the field. The results obtained from the two consecutive seasons revealed that plant vigour was found to be greater in ‘HRDBLM010’ and ‘Khumal Chauda Pat’ (4.7 in the 1 to 5 scale score). The highest leaf weight (65.1 g) was found in ‘HRDBLM010’, followed by ‘HRDBLM007’ (45.6 g) and ‘Khumal Chauda Pat’ (40.9 g). The highest number of leaves was produced by ‘HRDBLM004’ (50 leaves per plant), while leaf weight per plant was the highest in ‘HRDBLM010’ (691.1 g per plant) followed by ‘HRDBLM004’ (535.4 g per plant). Genotype ‘HRDBLM010' produced the highest leaf yield (54.52 MT ha-1), followed by 'HRDBLM004' (44.28 MT ha-1) and ‘HRDBLM007’ (41.65 MT ha-1). Thus, these three germplasms showed superiority among the seven tested germplasms and they could be recommended for cultivation in the mid-hill conditions of Nepal.

Mango fruit seed shells were used as starting materials to produce activated carbons for the capture of acetone, a typical volatile organic compound (VOC), from gaseous streams. This fruit waste presents high volatiles and low ashes contents, as expected for the lignocelulosic materials commonly used for the preparation of activated carbons. The starting material was hydrothermally treated at 180 or 250 °C for 5 h and the obtained hydrochars were activated with KOH solutions. The carbon samples were characterized by SEM, EDX, TG/DTA, Raman spectroscopy and textural analysis by physisorption. The adsorption capacity and adsorption cycles were investigated by TG. The hydrochars presented spherical morphology and the activated carbons derived from them presented heterogeneous micropore structures allowing to high capacity of acetone vapor removal, namely 472 mg/g, at 30 °C and 363 mg/g, at 50 °C. The results indicate that the adsorption capacity of the activated carbons is directly related to their Dubinin-Astakhov micropore surface areas and microporous volumes determined by NLDFT. The adsorption of acetone vapor showed a pseudo-first order kinetics and both external and intraparticle transport contributed for the overall process. Highly efficient and stable acetone vapor removal was observed over the activated carbons after five cycles.

Oil spills into ocean or coastal waters can result in significant damage to the environment via pollution of aquatic ecosystems. Absorbents based on reduced graphene oxide (rGO) foams have the capacity to remove minor or major oil spills. However, conventional chemical synthesis of rGO often uses petrochemical precursors, potentially harmful chemicals, and requires special processing conditions that are expensive to maintain. In this work, an alternative cost-effective and environmentally friendly approach suitable for large-scale production of high-quality rGO directly from used cooking sunflower oil is discussed. Thus, produced flaky graphene structures are effective in absorbing used commercial sunflower oil and engine oil, via monolayer physisorption in the case of used sunflower and engine oils facilitated by van der Waals forces, π–π stacking and hydrophobic interactions, π-cation ( H+) stacking and radical scavenging activities. From adsorption kinetic models, first-order kinetics provides a better fit for used sunflower oil adsorption (R2 = 0.9919) and second-order kinetics provides a better fit for engine oil adsorption (R2 = 0.9823). From intra-particle diffusion model, R2 for USO is 0.9788 and EO is 0.9851, which indicates that both used sunflower and engine oils adsorption processes follow an intra-particle diffusion mechanism. This study confirms that waste-derived rGO could be used for environmental remediation.

본 연구에서는 가래나무를 흡즙하는 Stomaphis matsumotoi Sorin, 1995를 국내 최초로 보고한다. 무시충의 생체 사진과 표본을 통한 형태 정보를 수록하였다.