Search

This study systematically explored the effect of the conditions adopted for the preparation of biochar on its adsorption performance. Palm tree fibre, sesame stalk and Platanus bark were chosen as raw materials and converted to biochar using a temperature-controlled vacuum carbonization method. This was then modified using KOH across various alkali–carbon ratios, activation temperatures and activation times, and the adsorption performance of the resulting samples was analyzed. Characterization analyses based on scanning electron microscopy (SEM), Brunner Emmet Teller (BET) measurements, Energy-dispersive X-ray spectroscopy (EDX) and Fourier transform infrared spectrometry (FTIR) revealed that after KOH activation, the biochar samples exhibited numerous defects and cross-sections, huge specific surface areas and abundant pore structures, all of which serve as adsorption sites. Characteristic functional groups(For example –OH and NH–), which significantly enhance adsorption, also increased. The iodine adsorption values of all three types of biochar initially increased and then decreased with the increase in pyrolysis temperature. An orthogonal test showed that the order, based on adsorption performance, of the three types of biochar prepared and modified under optimal conditions was palm tree fibre biochar (1628.55 mg.g−1) > sesame stalk biochar (1485.23 mg.g−1) > Platanus bark biochar (1360.43 mg.g−1). Their adsorption performances exceeded the national first-class product limit standard, implying that they exhibited good usability. This indicates that a lower alkali–carbon ratio can be used to obtain near-optimal results, thereby reducing corrosion and saving on production costs. [ABSTRACT FROM AUTHOR]

As a renewable new material with high void ratio, large adsorption surface area, and high adsorption rate, biomass carbon (BC) is a promising adsorbent, which has received wide attention for the degradation of dyes. However, physical adsorption cannot completely remove dyes, and there is also the risk of secondary pollution. ZnAl‐layered double hydroxide (ZnAl‐LDH) is a semiconductor photocatalyst with abundant active sites and excellent degradation efficiency. In this paper, we have designed a ZnAl‐layered double oxide@biomass carbon (ZnAl‐LDO@BC) formed by in situ grown LDH on the waste poplar wood as a synergistic adsorption and photocatalytic system. BC as a support could enhance the dispersity of layered double oxide (LDO), whereas LDO could provide photodegradation function to BC. Our studies indicate that the prepared ZnAl‐LDO@BC presents lower bandgap energy, higher surface area, and lower complexation efficiency of holes and electrons than delignified biomass (DB). As a result, ZnAl‐LDO@BC increased the removal rate of malachite green (MG) to 85.8%, which is 3.5 times higher than DB. The maximum removal rate was close to 98%, and the removal capacity was 1954 mg g−1 under an initial concentration of 200 mg L−1 of MG dye, and the possible mechanism of MG degradation was also investigated. In this study, the conversion of agroforestry wastes into high‐value materials applied to dye degradation provides a new pathway for the production of stable, sustainable, and superior photocatalytic material. [ABSTRACT FROM AUTHOR]

Copyright of Rare Metals is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Purposes] Electrocatalytic technology for converting CO2 into high-value-added fuels and chemicals has promising applications. However, developing electrocatalysts with superior performance still faces significant challenges. [Methods] In this study, wheat bran was used as the precursor of biomass carbon and the pyrolysis method was used to prepare nitrogen-doped biomass carbon materials (NC). By further coupling with CuO via a hydrothermal method, a series of CuO@NC composite materials were costructed. The crystalline phase, microscopic morphology, structure, and elemental valence states were analyzed by multiple characterization techniques. The electrocatalytic performance was investigated towards the electrocatalytic reduction of CO2. [Findings] Results indicate that the composite catalyst synthesized at 160 ℃ (CuO@NC-160) exhibits high selectivity towards ethylene, with a maximum faradaic efficiency of 26.85% at -1.18 V vs. RHE. This study presents a feasible pathway for fabricating low-cost and efficient CuO-based electrocatalysts.

Various biomass materials have been developed as precursor materials to fabricate carbon-based anodes for Li-ion battery (LIB) applications due to their inherent sustainability and low cost. However, the low theoretical specific capacity of carbon materials (273 mAh g−1) restricts their further application as an anode for LIBs. Herein, silicon/reed catkin composites (Si/RC) and silicon/apricot shell-derived carbon (Si/AC) are successfully fabricated, and their performances are evaluated as anode materials for LIBs. The Si/RC anode displays a reversible capacity of 318.4 mAh g−1 after 100 cycles at 200 mA g−1 and remains 229.3 mAh g−1 after 1000 cycles at 1 A g−1. This work discloses the feasibility and promising prospects of utilizing biomass reed catkins to prepare low-cost, porous, carbon-based materials for energy storage applications.

This work designed a one-step route to achieve the selective leaching of metals in the LiNi 0.3 Co 0.3 Mn 0.3 O 2 (NCM) cathode material and the preparation of high-performance carbon as anode material for LIBs. [Display omitted] • Carbothermal reduction combined with metal catalytic graphitization achieves simultaneously selective metal leaching and carbon material preparation. • The Li element in NCM was extracted in form of the water-soluble Li 2 CO 3 by water leaching without acid-base conditions. • The conversion of biomass carbon into graphitic carbon materials is achieved at low temperatures. • The decomposed gases disrupt the layered structure of NCM and help to expose more Li+ for extraction and conversion. • As anode material, the obtained carbon material shows high capacity and excellent rate capability in LIBs. The cathode materials of spent lithium-ion batteries (LIBs) have become the primary focus of research in today's recycling industry due to their high metal content and high purity. The recovering valuable metals from waste cathode alleviates resource shortage and provide security for human life. This work designed a one-step route to achieve the selective leaching of metals in the LiNi 0.3 Co 0.3 Mn 0.3 O 2 (NCM) cathode material and the preparation of high-performance carbon as anode material for LIBs. The biomass carbon source of bagasse as reducing agent disruptes the layered structure of the NCM material during calcination process which facilitates the synthesis of the water-soluble Li 2 CO 3 and enhance the leaching efficiency of Li+ ions. The leaching efficiency of Li element reaches as high as 96.62 % under the optimal condition. At the same time, the carbon source under catalysis by the metals is converted into high-performance anode active material with a specific surface area of 242.85 m2/g and crystal plane spacing of 15.23 nm. The anode in LIBs exhibits a discharge capacity of 532.5 and 224.5 mA g−1 at 0.1C and 3C, respectively. The specific capacity of 486.5 mA g−1 is maintained after 500 cycles at 1C. The full-cells with the carbon material electrodes after prelithium/presodiation also shows excellent cycle stability. This work provides an effective recycling strategy of the valuable metals in waste NCM and an incidental opportunity to the conversion of biomass to anode material for LIBs. [ABSTRACT FROM AUTHOR]