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Graphical abstract Highlights • Nitrogen-doped carbon supported Pd nanoparticles were prepared. • The catalyst demonstrated a high activity for the deoxygenation of carbonyl groups. • Reactions were performed at room temperature and 1 bar H 2 pressure. • Nitrogen in the catalyst acts as Lewis base to promote heterolytic cleavage of H 2. Abstract In this study, we have reported that a new catalyst of Pd nanoparticles supported on nitrogen-doped, highly porous carbon (Pd/NC-BT) could promote quantitative deoxygenation of carbonyl groups in a wide variety of aromatic compounds to give the fully saturated side-chain. The catalyst is unique in that it works under mild conditions at room temperature and standard hydrogen pressures. Examination of the catalytic process indicates that the presence of nitrogen atoms at the support surface and the highly porous catalyst structure are key factors contributing to the excellent catalytic performance. The nitrogen atoms act as Lewis bases sites to promote the heterolytic cleavage of H 2 in coordination with the Pd nanoparticles and the porous structure facilitates the mass transfer of the substrates to the catalytic sites. Hence, the catalyst exhibits sufficient power to reduce the alcohol groups of the intermediates to give alkyl groups under mild conditions while other functional groups in the substrate molecules remain unaffected. Furthermore, the Pd/NC-BT catalyst can be recycled without observable decrease in its activity (over at least after six cycles). [ABSTRACT FROM AUTHOR]

• Coffee grounds as a carbon source, it's environmentally sustainable. • High tetracycline removal rate is due to 1O 2 and electron transfer. • Point defects and carbonyl groups were critical for 1O 2 and electron transfer. • N/S-codoped carbons may provide an advanced strategy for green wastewater treatment. Nitrogen and sulfur-codoped porous carbons (SNCs) with porous structures and high surface areas were successfully synthesized employing coffee grounds, sodium bicarbonate and L-cysteine monohydrochloride as precursors. The SNCs were highly efficient for adsorption and exhibited outstanding catalytic performance for the oxidative degradation of tetracycline hydrochloride (TeC) solutions, especially at a calcined temperature of 700 °C (SNCs-700). The radical quenching, advanced in situ electron paramagnetic resonance (EPR) technology, PS decomposition rates and Linear Sweep Voltammetry (LSV) indicated that the excellent oxidative effectiveness of the PS/SNCs-700 system originated from the nonradical pathways (singlet oxygen (1O 2) and electron transfer). It's supposed that N and S doping can effectively create point defects, which could generate 1O 2 , while carbonyl groups were determined to be the main active sites contributing to the electron transfer. TeC degradation intermediates were also identified, three degradation pathways, revealing that the pre-adsorption significantly accelerated the nonradical oxidation pathways. This approach provides an innovative method for the large-scale production and application of high-quality catalysts in water treatment. [ABSTRACT FROM AUTHOR]

The sluggish oxidation kinetics of ferrate (Fe(VI)) at neutral and slightly alkaline pH impedes its rapid abatement of micropollutants in practical application. This work discovers that graphite (GP), a metal-free carbonaceous material, can be a promising material to improve the reactivity of Fe(VI) in the pH range of 7.0 − 9.0. The performance of the GP/Fe(VI) process for sulfamethoxazole (SMX) removal was further evaluated via altering the dosages of Fe(VI), GP, and SMX. Probe analysis and quenching experiments identified Fe(IV) and Fe(V) as the primary active species responsible for the removal of organic compounds in the GP/Fe(VI) system. The detailed activation mechanism of GP is discussed via analyzing the surface chemical changes of GP exposed to Fe(VI). It is found that the carbonyl groups on GP surface execute a critical role in Fe(VI) activation. The GP/Fe(VI) system shows powerful anti-interference ability to environmental background substances. Therefore, the new oxidation process proposed in this work holds a great application prospect for contamination remediation. Finally, we discuss the underlying degradation pathways of SMX by the GP/Fe(VI) system. This study not only develops a promising system for the removal of micropollutants but also provides an in-depth insight into the activation mechanism of metal-free carbonaceous material in Fe(VI) oxidation process. [Display omitted] • GP can improve the oxidation activity of Fe(VI) to eliminate various micropollutants. • Fe(IV) and Fe(V) are the main active oxidants in the GP/Fe(VI) system. • The carbonyl group on GP surface plays a vital role in activating Fe(VI). • The GP/Fe(VI) system shows an excellent environmental adaptability. [ABSTRACT FROM AUTHOR]

Summary: In order to evaluate the effect of steam addition during meat roasting, beef sirloin steaks were cooked at five humidities (0%, 25%, 50%, 75% and 100%) under 230 °C to a centre temperature of 71 °C. With increased humidity, heating rate generally increased and the cooked steak gradually lost the typical roasted appearance. Thiobarbituric acid‐reactive substances (TBARS) values generally increased, while carbonyl groups were not affected. Increased humidity promoted the formation of volatile aldehydes and alcohols, while pyrazines decreased significantly from 0% to 25% humidity. Steam‐assisted roasting inhibited the formation of heterocyclic aromatic amines (HAAs; except for IQ and Norharman). However, further increase in humidity (larger than 25%) did not have additional inhibition effect. Based on the results, it is recommended to roast beef with steam addition to reduce toxic HAAs, but the humidity should be kept at a relatively low level to maintain a typical roasted appearance and flavour profile. [ABSTRACT FROM AUTHOR]

The acceleration of Fe(III)/Fe(II) conversion in Fenton systems is the critical route to achieve the long-lasting generation of reactive oxygen species towards the oxidation of refractory contaminants. Here, we found that waste leather derived porous carbon materials (LPC), as a simple and readily available metal-free biochar material, can promote the Fe(III)/H 2 O 2 system to generate hydroxyl radicals (•OH) for oxidizing a broad spectrum of contaminants. Results of characterizations, theoretical calculations, and electrochemical tests show that the surface carbonyl groups of LPC can provide electron for direct Fe(III) reduction. More importantly, the graphitic-N on surface of LPC can enhance the reactivity of Fe(III) for accelerating H 2 O 2 induced Fe(III) reduction. The presence of LPC accelerates the Fe(III)/Fe(II) redox cycle in the Fe(III)/H 2 O 2 system, sustainable Fenton chain reactions is thus initiated for long-lasting generation of hydroxyl radicals without adding Fe(II). The continuous flow mode that couples in-situ Fenton-like oxidation and LPC with excellent adsorption catalytic properties, anti-coexisting substances interference and reusability performance enables efficient, green and sustainable degradation of trace organic pollutants. Therefore, the application of metal-free carbon materials in Fenton-like system can solve its rate-limiting problem, reduce the production of iron sludge, achieve green Fenton chemistry, and facilitate the actual engineering application of economic and ecological methods to efficiently remove trace organic contaminants from actual water sources. [Display omitted] • Waste leather-derived porous carbon can effectively boost Fenton oxidation. • H 2 O 2 can act as an electron donor for green and sustainable Fenton oxidation. • Surface nitrogen of LPC can elevate the reactivity of Fe(III) species. • Sustainable removal of trace refractory organic pollutants was achieved. • Hydroxyl radical induced oxidation pathway of DEP was proposed. [ABSTRACT FROM AUTHOR]