The emergence of green methods for the synthesis of graphene-based composites became the gateway for the solution of pollution and economic synthetic methods. Herein, we reported a single step in situ synthesis of reduced graphene oxide sheets decorated with silver nanoparticles (CRG–Ag nanocomposite) using custard apple leaf extract as an effective reducing and stabilizing agent. The ultraviolet–visible, Fourier transform infrared and Raman techniques revealed a primary confirmation about the formation of the said nanocomposite. The X-ray diffraction studies confirmed the face-centred cubic crystal structure of silver nanoparticles (Ag NPs) of 30 nm in size. The high-resolution scanning electron microscope spectra revealed the uniform distribution of Ag NPs on the graphene sheets. This simple, novel and rapid approach enabled a facile production of homogeneously deposited Ag NPs on graphene sheets. Thus synthesized CRG–Ag nanocomposite showed excellent photocatalytic efficiency of 96% in 2 h under sunlight using methylene blue as a model pollutant.

본 연구는 양액 내 존재하는 다량 영양소의 농도를 실시간으로 측정하기 위해 이온 선택 전극 (ISE) 으로 구성된 임베디드 시스템의 개발을 보여준다. NO3, K 및 Ca 이온을 감지하기위한 PVC ISE, H2PO4를 감지하기위한 코발트 전극, 기준 전극, 샘플 용액이 담기는 챔버, 펌프 및 밸브를 사용하여 측정하는 시스템으로 구성된다. 양액 샘플양 조절과 데이터 수집을 위해서 데이터 Due 보드가 사용되었고, 각각의 샘플 측정 전에, 측정 중 발생하는 드리프트를 최소화시키기 위해 2 점 정규화 방법을 사용하였다. PVC 멤브레인을 기반으로 한 NO3 및 K 전극의 농도 예측 성능은 표준 분석기의 결과와 근접한 일치 (R2 = 0.99) 나타내며 만족스러운 결과를 나타냈다. 하지만, Ca Ⅱ 이온 투과체 제조된 Ca 전극은 고농도 양액 농도에서 Ca 농도를 55 %로 낮게 측정하였다. 코발트 전극 기반 인산 측정은 반복측정 중에 발생한 코발트 전극의 불안정한 신호로 인해 표준 방법과 비교하여 45 ~ 155 mg / L의 인산 농도 범위에서 24.7 ± 9.26 %의 비교적 높은 오차를 나타냈다. 수경 P 감지의 예측 능력을 향상시키기 위해 코발트 전극의 신호 컨디셔닝에 대한 추가 연구가 필요함으로 판단된다.

Carbon materials with tailorable structures and superior properties have great potential applications in environmental protection, energy conversion, and catalysis. Plant biomass as abundant and green non-toxic raw materials has been considered as good precursors for synthesizing heteroatom-doped carbon materials. However, few studies have been reported on the different natures of carbon materials derived from different parts of the same plant biomass. In this study, we prepared carbon materials from the petioles and blades of apricot leaves by direct pyrolysis without additives. Detailed characterizations indicate that these two carbon materials are similar in element composition and graphitization degree, but differ greatly in surface area and pore volume. These differences can be attributed to the different contents of inorganic salts, vascular bundles, and proteins in petioles and blades. When used as catalysts for the oxidation of ethylbenzene, the petiole-derived carbon shows better catalytic performance than the blades derived carbon due to its high surface area, large average pore size, and doped nitrogen atoms. Furthermore, the carbon catalysts derived from the petioles and blades of poplar leaves and parasol tree leaves show the same difference in catalytic reaction, implying that the above-mentioned conclusion is rather universal, which can provide reference for the synthesis of carbon materials from leaves.

A highly functional, environmentally friendly carbonaceous adsorbent material using black liquor (a by-product from the pulp manufacturing) was produced and characterized. This study showed the effect of self-chemical activation driven by inherent alkali, originated from the unique composition of black liquor. A preparation of the micropore-dominant activated carbon was made in an easy and simple manner. The specific surface areas of samples were found to be 718–1591 m2/ g variated upon heat treatment conditions. The sample activated at 850 °C (50 min as retention time) showed the maximum specific surface area of 1591 m2/ g with 13.6% as a production yield. Considering the factors influencing pore structure of activated carbon materials in this study, it was confirmed that mesopore-related surface area increased gradually as the activation temperature and retention time increased. It is noteworthy to address that economically valuable micropore-dominant activated carbon can be produced by a simple heat treatment of the waste material, black liquor. The activated carbon sample derived from black liquor can be applied to various fields, such as environment and energy storage.