Biochar最新文献

Abstract

Bio-tar extra-produced from biomass pyrolysis is prone to pose a threat to environment and human health. A novel N-doped porous electrode from bio-tar was produced under dual-activation of urea and KOH in this study. One-pot dual-activation played significant roles in N-functional group and micro-mesoporous structure, which resulted in the carbon material with the highest of nitrogen content (4.08%) and the special surface area (1298.26 m²·g⁻¹). Specifically, the potential mechanisms of pore formation and N-doping in the one-pot dual-activation strategy were also proposed as a consequence, the one-pot dual-activated carbon material displayed excellent electrochemical performance with the highest capacitance of 309.5 F·g⁻¹ at 0.5 A·g⁻¹, and the unipolar specific capacitance remained with cyclic characteristics of 80.1% after 10,000 cycles in two-electrode symmetric system. Furthermore, the one-pot dual-activation strategy could create a profit of $1.64–$2.38 per kilogram of bio-tar processed without considering the initial investment and labor costs, which provides new perspectives for the utilization of waste bio-tar.

Due to the rising need for clean and renewable energy, green materials including biochar are becoming increasingly popular in the field of energy storage and conversion. However, the lack of highly active and stable electrode materials hinders the development of stable energy supplies and efficient hydrogen production devices. Herein, we fabricated stable, conductive, and multifunctional chitosan microspheres by a facile emulsion crosslinking solution growth and hydrothermal sulphuration methods as multifunctional electrodes for overall water splitting driven by supercapacitors. This material possessed three-dimensional layered conductors with favorable heterojunction interface, ample hollow and porous structures. It presented remarkably enhanced electrochemical and catalytic activity for both supercapacitors and overall water electrolysis. The asymmetric supercapacitors based on chitosan biochar microsphere achieved high specific capacitance (260.9 F g⁻¹ at 1 A g⁻¹) and high energy density (81.5W h kg⁻¹) at a power density of 978.4 W kg⁻¹. The chitosan biochar microsphere as an electrode for electrolyze only required a low cell voltage of 1.49 V to reach a current density of 10 mA cm⁻², and achieved excellent stability with 30 h continuous test at 20 mA cm⁻². Then, we assembled a coupled energy storage device and hydrogen production system, the SCs as a backup power source availably guaranteed the continuous operation of overall water electrolysis. Our study provides valuable perspectives into the practical design of both integrated biochar-based electrode materials and coupled energy storage devices with energy conversion and storage in practical.

Graphical Abstract

In the last few decades, sulfonated carbon materials have garnered significant attention as Brønsted solid acid catalysts. The sulfonation process and catalytic activity of sulfonated biochar can be influenced by the aromaticity and degree of condensation exhibited by biochar. However, the relationships between the aromaticity, sulfonating ability, and resultant catalytic activity are not fully understood. In this study, biochar samples pyrolyzed at 300–650 °C exhibiting different aromaticity and degrees of condensation were sulfonated and employed as sulfonate-bearing solid catalysts for hydrolytically removing tylosin. They exhibited excellent hydrolytic performance and their kinetic constants were positively correlated with the total acidity and negatively correlated with their aromaticity. This study has uncovered the relationship between the structure, properties, sulfonating ability, and subsequent hydrolytic performance of biochar samples. It was observed that the aromaticity of biochar decreased as the pyrolysis temperature increased. Lower pyrolysis temperatures resulted in a reduced degree of condensation, smaller ring size, and an increased number of ring edge sites available for sulfonation, ultimately leading to enhanced catalytic performance. These findings provide valuable insights into the fundamental chemistry behind sulfonation upgrading of biochar, with the aim of developing functional catalysts for mitigating antibiotics in contaminated water.

Graphical Abstract

Biochar has a large specific surface area, well-developed pore structure, abundant surface functional groups, and superior nutrient supply capacity, which is widely available and environmentally friendly with its advantages in waste resource utilization, heavy metal(loid) remediation, and carbon storage. This review focuses on the interactions between biochar (including raw biochar, functional biochar (modified/ engineered/ designer biochar), and composite biochar) and rhizosphere during the remediation of soil contaminated with heavy metal(loid)s (Pb, As, Cd, Hg, Co, Cu, Ni, Zn, Cr, etc.) and the effects of these interactions on the microbial communities and root exudates (enzymes and low-molecular-weight organic acids (LMWOAs)). In terms of microorganisms, biochar affects the composition, diversity, and structure of microbial communities through the supply of nutrients, provision of microbial colonization sites, immobilization of heavy metal(loid)s, and introduction of exogenous microorganisms. With regard to root exudates, biochar provides electron transfer support between the microorganisms and exudates, regulates the secretion of enzymes to resist the oxidative stress stimulated by heavy metal(loid)s, ameliorates rhizosphere acidification caused by LMWOAs, and promotes the activity of soil enzymes. The roles and mechanisms of biochar on rhizosphere soils are discussed, as well as the challenges of biochar in the remediation of heavy metal(loid)-contaminated soils, and the issues that need to be addressed in future research are foreseen.

Graphical Abstract

The widespread organic pollutants in wastewater are one of the global environmental problems. Advanced oxidation processes (AOPs) are widely used because of their characteristics of high efficiency and strong oxidation. However, AOPs may have some defects, such as incomplete mineralization of organic pollutants and the generation of toxic by-products during the degradation process, thus it is essential to seek efficient and green wastewater treatment technologies. Coupling different AOPs or other processes is beneficial for the mineralization of pollutants and reduces ecological risks to the environment. It is worth noting that carbonaceous materials (CMs) have received widespread attention and application in the degradation of organic pollutants in water by advanced oxidation coupling processes (C-AOPs) due to their excellent physicochemical properties in recent years. However, the behaviors and mechanisms of C-AOPs based on CMs on the degradation of organic pollutants are still unknown. Therefore, it is essential to comprehensively summarize the recent research progress. In this review, the applications of different CMs in C-AOPs were reviewed first. Secondly, the synergistic mechanisms of the C-AOPs based on different CMs were discussed. Then, toxic intermediates were explored and important toxicity assessment methods were proposed. Finally, the application potential of the C-AOPs in the future and the challenges were proposed. This review provides an important reference for the application and optimization of the C-AOPs in organic wastewater treatment in the future.

Graphical Abstract

In this study, an adsorbent (LCB) with rich honeycomb structure was prepared from cork waste generated from furniture factories for efficient adsorption of excess phosphorus (P) from wastewater. This adsorbent was successfully prepared in only one step, in situ precipitation method, which greatly simplified the synthesis process. Kinetic studies showed that when the initial concentration (C₀) of wastewater was 10 mg P L⁻¹, the P in the water could be completely adsorbed within 20 min. The adsorption efficiency of phosphorus was significantly improved compared to previous studies. When the C₀ of pollutant and the dosage of LCB were 20 mg P L⁻¹ and 0.5 g L⁻¹, respectively, the removal rate of P exceeded 99% in the pH range of 3–10, which indicates the wide applicability of LCB. In addition, the P adsorption capacity of LCB was 82.4% of its initial value after nine adsorption–desorption cycles, indicating that LCB has a high stability and can be widely used in different water environments. Therefore, LCB is a promising material for the treatment of P-containing wastewater.

Graphical Abstract

Pyrolysis is an effective technology for treating and utilizing biogas residue. To explore the phosphorus (P) supply capacity of the biochar generated from biogas residue of Eichhornia Crassipes, the P speciation of E. crassipes biogas residue and biomass during pyrolysis (300–700 °C) was analyzed by combining sequential chemical extraction, ³¹P nuclear magnetic resonance (NMR) and P K-edge X-ray absorption near edge structure (XANES) spectroscopy. Pyrolysis treatment promoted the conversion of amorphous Ca-P phases in biogas residue and biomass into crystalline hydroxyapatite (HAP) phase, which matched the formation of stable HCl-P pools in the biochar derived from biogas residue (AEBs, 22.65–82.04%) and biomass (EBs, 13.08–33.52%) in the process of pyrolysis. Moreover, the total P contents in AEBs (19.43–28.92 mg g⁻¹) were higher than that of EBs (3.41–5.26 mg g⁻¹), indicating that AEBs had a great P reclamation potential. The P release kinetics from AEBs and EBs in water were evaluated via an incubation experiment for 360 h. The P release from both AEBs and EBs conformed to the pseudo-second order kinetics model (R² > 0.93), but their P release behaviors were different. The P release of AEBs conformed to the diffusion-re-adsorption model, while that of EBs accorded with the diffusion-dissolution model. The diffusive gradients in thin-films (DGT) analysis showed that AEBs could significantly increase soil available P content as compared with EBs. Hence, the biochar produced from biogas residue of E. crassipes via pyrolysis has a good application potential as a P fertilizer.

Graphical Abstract