Low Carbonization Research Articles

Potential assessment of coordinated regulation of power load of emerging industrial users based on extreme scenarios of electric vehicle aggregators

AbstractWith the advancement of industrial low carbonization and electrification, emerging industrial production technologies have the characteristics of high‐power consumption and significant impact load. In the context of increasing global climate change, frequent extreme weather events have brought serious challenges to the balance of power and electricity in the power system, and have a significant impact on the production scheduling of industrial users, especially industrial users using electrified production technology. First, based on the representative high‐power industrial users of hydrogen reduction steel plants and internet datacentres (IDC), this paper establishes a flexible resource scheduling optimization model for single industrial users, and considers the collaborative relationship between multi‐user flexible resources to establish a collaborative scheduling optimization model for industrial users. Then, considering the charging and discharging characteristics of electric vehicles (EV) in extreme scenarios, the redundant capacity of EVs is aggregated by EV aggregators and sold to industrial users, and a collaborative scheduling optimization model of EV aggregators and industrial users is established. Finally, the effectiveness of the proposed model and algorithm is verified by simulation analysis. Compared with the traditional industrial user production optimization, the proposed model can tap the potential of multi‐agent scheduling operation in extreme scenarios.

Financial Mechanism for Sustainable Development of the Marine Economy with Respect to Technology, Digitalization, and Low Carbonization

This study explores the impact of regional financial development on the sustainable growth of the marine economy across 14 coastal cities in Guangdong Province from 2004 to 2022. To assess this, a comprehensive index system was developed to measure marine economic sustainability, incorporating key factors such as capital investment, production efficiency, and processing and trade. The findings indicate that financial development significantly enhances the sustainable growth of the marine economy. However, the interaction between financial development, technology digitalization, and low-carbon initiatives leads to diminishing returns in terms of sustainability. Through the use of the Moran index and the spatial Durbin model, the analysis reveals a dual outcome: while financial development positively influences a city’s marine economic sustainability, it exerts negative spillover effects on neighboring cities. Previous studies have primarily focused on the relationship between financial development and the marine economy at the national or provincial level, leaving a gap in understanding these dynamics at the city level. Furthermore, the coordination between financial development and marine economic sustainability across cities within the same region remains largely unexplored. This study addresses these gaps by investigating city-level dynamics and examining intercity coordination between financial development and marine economic growth. The results offer a novel perspective for policymakers, highlighting strategies to balance regional financing for the marine economy with targeted investments in science, technology, digitalization, and low-carbon initiatives. This approach seeks to optimize resource allocation and mitigate potential substitution effects. Ultimately, this research contributes to a more nuanced understanding of the complex interplay between financial development and the marine economy at both city and regional levels.

Surface charge alteration of charcoal derived from bamboo leaves and understanding the interaction with anionic and cationic dye

Cost-effective adsorbents derived from regenerative sources provide a sustainable solution to the pressing environmental pollution challenges. Conventional studies often rely on biochar-based adsorbents obtained at high carbonization temperatures in an induced environment. The present study explored the efficacy of carbon derived from the stems (CBS) and leaves (CBL) of bamboo plants as efficient dye adsorbents at low carbonization temperatures. CBL carbonized at 350 °C exhibited a remarkable dye adsorption efficiency of 90%, significantly outperforming CBS, which achieved only 39% efficiency. To enable the adsorption of both dyes, heterophase metal oxides, specifically Fe-doped ZnO and ZnFe2O4 were incorporated. Zeta potential measurements revealed a transition from negative to positive values with metal oxide incorporation, suggesting alterations in the surface acidity and functional group composition. The adsorption performance of the composite (WC20) sample was evaluated using Congo Red (CR) and Crystal Violet (CV) dyes. Comprehensive studies on the adsorption kinetics, isotherm modeling, and thermodynamics have been conducted to identify WC20 as the most effective composite. The equilibrium adsorption data aligned well with the Langmuir isotherm model, demonstrating maximum adsorption capacities of 65.31 mg g−1 for CR and 38.05 mg g−1 for CV at room temperature of 298 K with constant pH. Thermodynamic analysis indicated a hybrid adsorption mechanism, wherein CR adsorption was predominantly driven by chemisorption, whereas CV adsorption was governed by physisorption. Mechanistic insights have revealed that electrostatic interactions and π–π stacking play crucial roles in dye removal. These findings underscore the potential applicability of WC20 as a cost-effective and efficient adsorbent for the remediation of both cationic (CV) and anionic (CR) dyes in wastewater, highlighting its viability for future environmental management and pollution mitigation strategies.

Defect-rich hard carbon designed by heteroatom escape assists sodium storage performance for sodium-ion batteries

Sodium-ion batteries (SIBs) avoids the use of expensive cobalt element, and the abundance of sodium element is high, so it shows great application potential, and the development of sodium-ion battery materials is of great value. Biomass precursors have the advantages of low cost and widely and sufficiently distributed resources, and embody the environmental concept of waste utilization, however, the poor reversible specific capacity and initial coulombic efficiency (ICE) of pristine corn stover-derived hard carbons (CSHCs) limit their practical application value. In this paper, we propose a method to increase the reversible specific capacity of hard carbon and maintain high ICE, introduce heteroatoms into graphene-like nanosheets at low carbonization temperature, then escape heteroatoms through high pyrolysis temperature, create defects in the graphene-like carbon layer and expand the (002) layer spacing. Density functional theory (DFT) calculations show that defects are beneficial to the adsorption of Na+ on graphene-like nanosheets, and Na+ have a lower diffusion barrier between layers rich in defects and extended (002) layer spacing. Compared with the conventional low pyrolysis temperature heteroatom doping process, the present method exhibits superior ICE. In the ester-based electrolyte, the modified hard carbon (D-CSHC) exhibits a superior specific capacity of 284.5 mAh/g and an ICE of 85.9 % as compared to the pristine corn stover-derived hard carbon (233.5 mAh/g, 72.7 %). In addition, the capacity retention rate was 92.6 % after 500 turns of constant current cycles at 0.15 A/g.

Mercerization-enhanced cellulose-II cotton fiber-based low-temperature hard carbon for sodium-ion batteries

Hard carbons from cellulose are highly regarded as promising anode options for sodium-ion batteries (SIBs). However, a high carbonization temperature (>1300 °C) is usually required to obtain high-performance hard carbons, which leads to high-energy consumption and high cost. Moreover, hard carbons generally have poor rate capability and unsatisfactory cyclability which restrict their commercial applications. Herein, a low-temperature (900 °C) approach for the preparation of high-quality hard carbons for SIBs from waste cotton fibers is reported. It involves a mercerization pretreatment to convert cellulose-I cotton fibers into cellulose-II structure and dissolve the amorphous cellulose to form highly crystalline cellulose. This pretreatment process benefits forming abundant pseudo-graphitic structures at a low carbonization temperature of 900 °C. Consequently, the mercerized cotton fibers-based carbons (MCFC) exhibit excellent sodium storage properties, possessing a high capacity (316 mAh g−1 at 0.1 A g−1), high-rate capability (210 mAh g−1 at 10 A g−1), and long-term cyclability (83.2 % retention after 3000 cycles). This mercerization approach coupled with waste cotton fibers provides a sustainable pathway for the preparation of high-quality hard carbons for SIBs.

Low temperature carbonization and synergistic flame retardancy of cotton fabric coated by phosphorus‑nitrogen flame retardants

To solve the problems of flammability and smoldering of cotton fabric, its flame-retardant finishing was executed with biomass wool keratin (WK) and cyclic phosphate ester (CPE) through the soaking and baking process. The synergistic mechanism of WK low-temperature melting and CPE catalytic dehydration prompted the formation of protective carbonization layer on cotton fabric surface, and this protective layer reduced its pyrolysis rate, inhibited the production of combustible materials and improved its flame retardancy. The results of synchronous thermal analysis indicate that the initial decomposition temperature of WK and CPE is lower than that of cotton fabric, and they precede the endothermic degradation before fabric main body. This effectively promotes the low-temperature carbonization of cotton fabric and inhibits its pyrolysis. The initial decomposition temperature of WK/CPE treated fabrics advances by 47.9 °C–97.8 °C, presenting significant low-temperature carbonization trend. Moreover, they form 3.0 %–20.0 % aromatic structural char before the pyrolysis of cotton cellulose due to the low-temperature dehydration and carbonization reactions. The damage length after vertical burning is only 4.0 cm for treated fabric with five layers, its after-flame and smoldering disappear, and its limiting oxygen index value increases to 28.7 %. This research provides an effective idea for the flammability and smoldering problems of cotton fabric.

Hybrid fiber reinforced ultra-high performance coal gangue geopolymer concrete (UHPGC): Mechanical properties, enhancement mechanism, carbon emission and economic analysis

The low carbonization of ultra-high performance concrete (UHPC) has become a hot topic for sustainable development in the construction industry. Calcined coal gangue was used as aggregate and binder to prepare ultra-high performance coal gangue geopolymer concrete (UHPGC) in this paper. The hybrid reinforcement effect of steel fibers, calcium carbonate whiskers (CW), and carbon nanotubes (CNTs) on UHPGC was studied in the experiment. The results indicated that when the mixing ratio of straight steel fibers and hooked-end steel fibers was 2:1, the 28 d-compressive strength of UHPGC reached 145.94 MPa. However, excessive hooked-end steel fibers deteriorated the reinforcement effect of adjacent fibers and reduced the mechanical properties of UHPGC. CW and CNTs had a more significant improvement in the flexural properties of UHPGC. The bridging effect of CNTs and CW dispersed the stress on the matrix and delayed the formation and development of micro-nano cracks. Meanwhile, CNTs and CW improved the fiber bridging energy dissipation, thereby improving the flexural properties of UHPGC. The UHPGC had the highest flexural strength and flexural deflection of 13.59 MPa and 4.12 mm, respectively. The UHPGC prepared in this paper had lower carbon emissions and economic costs compared to traditional UHPC. Overall, this study provided valuable references for the resource utilization of coal gangue and the multi-scale strengthening and toughening of UHPGC.

The Future of Environmental Engineering Technology: A Disruptive Innovation Perspective

Scientific and technological revolutions and industrial transformations have accelerated the rate of innovation in environmental engineering technologies. However, few researchers have evaluated the current status and future trends of technologies. This paper summarizes the current research status in eight major subfields of environmental engineering—water treatment, air pollution control, soil/solid waste management, environmental biotechnology, environmental engineering equipment, emerging contaminants, synergistic reduction of pollution and carbon emissions, and environmental risk and intelligent management—based on bibliometric analysis and future trends in greenization, low carbonization, and intelligentization. Disruptive technologies are further identified based on discontinuous transformation, and ten such technologies are proposed, covering general and specific fields, technical links, and value sources. Additionally, the background and key innovations in disruptive technologies are elucidated in detail. This study not only provides a scientific basis for strategic decision-making, planning, and implementation in the environmental engineering field but also offers methodological guidance for the research and determination of breakthrough technologies in other areas.

Accelerated Bridge Construction Case: A Novel Low-Carbon and Assembled Composite Bridge Scheme

Modern bridge construction towards a higher degree of low carbonization and assembly has been the general trend, while developing and broadening the low-carbon and assembled-oriented Accelerated Bridge Construction (ABC) technology can better realize the trade-offs between construction quality, efficiency, cost and sustainability. In the current mainstream ABC technologies such as precast-assembled concrete bridge and assembled steel bridge schemes, it is difficult to achieve an excellent balance between the above multicriterion trade-offs. To this end, this paper proposes a novel low-carbon and assembled composite bridge scheme as an innovative case of ABC technology based on a 26.7 km-length urban viaduct project in China with urgent environmental protection and assembly demands. Construction sustainability, the comprehensive economy and low-carbon performance are well balanced by the collaborative application of new steel–concrete composite structures, the rapid assembly interface design and low-carbon material technologies. The proposed scheme has been applied to a completed real-scale bridge, and the whole construction process only experienced 105 days of effective time, accompanied with slight environmental interference and construction noise and a small amount of labor and equipment input. In addition, the safety of the bridge, the rationality of the design concept and the calculation method have been verified by the static and dynamic loading tests of the real-scale bridge.

Low temperature carbonization, smoke suppression and durable flame retardancy of cotton fabric spray-assisted coated by phosphorus nitrogen silicon composite system

To solve the problems of flammability, smoldering, smoking and flame retardant durability of cotton fabric, flame retardant fininshing was executed using spray assisted self-assembly method, and P/N/Si synergistic flame retardant system was constructed by polyethylene imine (PEI), phytic acid (PA) and 3-aminopropyltriethoxysilane (APTES). Cotton cellulose carbonized at low temperature prompting by PA catalytic effect, and this cooperated with PEI thermal decomposition to endow cotton fabric with flame retardancy and smoking suppression by reducing its pyrolysis rate at high temperature and lessening combustible products. Meanwhile APTES as silane coupling agent further improved its flame retardant durability and smoke suppression effect. The synchronous thermal analysis results indicate that cotton fabrics treated by PA/PEI/APTES composite system present significant low-temperature carbonization trend, and their initial decomposition temperatures advance by 46.5℃-75.9℃. Moreover, they form 4.6 %-44.9 % aromatic structure char through dehydration and carbonization reactions during the low-temperature carbonization process, improving their thermal stability at high temperature, and their after-flame and smoldering phenomena disappear. The damaged length of treated fabric with five layers reduces to 5.0 cm, its limiting oxygen index reaches 33.7 %, and it presents excellent flame retardant durability and smoke suppression effect. This low-temperature carbonization mechanism possesses importantly innovative significance for the flame retardant finishing of cotton fabric, and it not only more actively guides the selection of flame retardants to make them match with the material required, but provides a new thinking method for flame retardant material research in the future.

Operational characteristics of solar-gas combined heating water system with phase change heat storage units for oilfield hot water stations

To achieve the low carbonization heating purpose of oilfield hot water stations, an innovative solar-gas combined heating water system with phase change heat storage (PCHS) units is proposed. The operating characteristics of the combined heating system utilizing PCHS and traditional water heat storage (WHS) are compared. The impact of the phase transition temperature of phase change materials (PCMs) on the operational characteristics is simultaneously investigated. The findings demonstrate that the utilization of PCHS can yield a reduction in gas consumption for the combined heating system by about 7.02 % compared to WHS. Moreover, the combined heating system achieves better energy savings when the phase transition temperature is slightly lower than the heat demand temperature at the load end. The heating demand of gas boilers is reduced by about 75.60 GJ during the summer and autumn when the phase change temperature changes from 80 °C to 62 °C. This study provides theoretical guidance and references for the industrial application of solar heating systems (SHSs) that utilize PCHS units.

Controlling the graphite-like microcrystalline structure of lignin-based ultrafine carbon fibers via the design of condensed structures

Obtaining lignin-based graphite-like microcrystallites at a relatively low carbonization temperature is still very challenging. In this work, we report a new method based on condensed structures, for regulating graphite-like microcrystalline structures via the incorporation of 4,4′-diphenylmethane diisocyanate (MDI) into the main structure of lignin. The effects of MDI on the thermal properties of lignin and the graphite-like microcrystalline structure of lignin-based ultrafine carbon fibers were extensively studied and investigated. The incorporation of MDI decreased the thermal stability of lignin, increased the carbon yield and enhanced the formation of graphite-like microcrystallites, which are beneficial for reducing energy consumption during the preparation of lignin-based carbon fibers. The modified lignin-based ultrafine carbon fibers (M-LCFs) demonstrated satisfactory electrochemical performance, including high specific capacitance, low charge transfer resistance, and good cycle performance. The M-LCFs-3/2 electrode had a specific capacitance of 241.3 F g−1 at a current density of 0.5 A g−1, and a residual ratio of 90.2 % after 2000 charge and discharge cycles. This study provides a new approach to control the graphite-like microcrystalline structure and electrochemical performance while also optimizing the temperature.

Preparation of N and O doped coal tar pitch based porous carbon for supercapacitor electrode

Coal tar pitch (CTP) is mainly composed of a mixture of polycyclic aromatic hydrocarbons, is almost hydrophobic, and has a low heteroatom content, which limits its surface function. During carbonization, it is prone to condensation and difficult to form pore structures, resulting in poor electrochemical performance for carbon electrode materials. Herein, nitrogen (N) and oxygen (O) doped hierarchical porous carbon (C-ANOCTP) was prepared by HNO3 oxidation and KOH activation using CTP as carbon precursor. The oxidation of HNO3 remarkably increases the hydrophilic functional groups containing N and O on the surface of CTP, improves the hydrophilicity of CTP surface, facilitates the activation process of KOH, promotes the development of carbon material pore structure and the generation of active sites, as well as the formation of defect structures. The specific surface area of C-ANOCTP obtained is 1130 m2/g, with O content of 10.29 at% and N content of 2.37 at%. The specific capacitance of C-ANOCTP in a three-electrode system with 6 M KOH electrolyte is as high as 410.51 F/g at 0.5 A/g. A symmetric supercapacitor is assembled in a 6 M KOH electrolyte using C-ANOCTP as electrode. When the power density is 25 W/kg, the energy density is 10.24 Wh/kg. After 10,000 cycles, the capacitance retention rate is still 90.03% and the coulomb efficiency is 100%. The high N and O content of porous carbon is prepared by simple HNO3 oxidation synergistic KOH activation and low temperature carbonization, which shows excellent electrochemical properties in supercapacitors, making CTP an ideal candidate material for high energy density supercapacitors.

Novel Evaluation Method for Cleaner Production Audit in Industrial Parks: Case of a Park in Central China

With respect to peak carbon and carbon neutrality, China’s economic structure is developing towards low carbonization, circulation, and cleanliness. There is an urgent need to expand the scope of cleaner production audits, improve cleaner production efficiency, and promote cleaner production through regional coordination. The 14th Five-Year National Cleaner Production Implementation Plan proposed selecting 100 parks or industrial clusters to conduct an overall cleaner production audit innovation pilot. To promote the coordinated development of cleaner production areas, this study constructed a set of cleaner production index systems for industrial parks, established an evaluation model based on the binary semantic evaluation method, and selected an industrial park in central China as an audit pilot. The binary group θ1=(2, −0.1084) of the rating results was determined to be a cleaner production park. Based on the evaluation results, the clean production potential of the park was analyzed, and suggestions for clean production were put forward. Sixteen representative enterprises in the park were selected to build twenty-one ecological chains, providing reasonable suggestions for constructing a systematic and circular enterprise symbiosis network.

Energy performance analysis of solar assisted gas-fired boiler heating system for floating roof oil tank

An innovative solar assisted gas-fired boiler heating system for floating roof oil tank is proposed to achieve the low carbonization of the conventional crude oil heating method. However, the dynamic energy transport performance of the proposed heating system affected by the key engineering parameters (crude oil capacity load, mass flow rate of heat transfer fluid (HTF), crude oil initial temperature) is unclear, which hinders the engineering application of this technology. In this regard, a simulation platform for solar assisted gas-fired boiler heating system for floating roof oil tank is established, and the above mentioned engineering parameters are investigated. The results show that under the condition of combined heating of evacuated tube solar collector (ETSC), phase change heat storage tank (PCHT), and auxiliary heat source (AHS), the system can achieve stable operation by means of controllers. With the increase of crude oil capacity load, the time for the crude oil to reach its design temperature is delayed, and up to 84.21% time lag is recorded. Apart from the contribution of AHS, the maximum annual heat supply of 43.37% is provided by PCHT and ETSC, presenting good energy-saving potential. Increasing HTF mass flow rate and crude oil initial temperature is a good strategy to reduce the output of AHS, in which the annual heat supply proportion of AHS decreases by 2.25% and 2.05%, respectively. The operating stability of proposed system is enhanced under the condition of higher HTF mass flow rate, compared to the 3.5 kg/s HTF mass flow rate, the safe reserve time increases by 31.44% for 7 kg/s and 34.24% for 14 kg/s HTF mass flow rate, respectively.

Chitosan-derived carbon aerogel modified with lignin carbon quantum dots for efficient solar evaporation

Solar-powered desalination technology offers outstanding benefits in providing clean, safe water and alleviating global freshwater shortages. However, the low evaporation rate, poor salt resistance and high cost limit the development of solar evaporators. Inspired by plant transpiration, a solar evaporator was fabricated from lignin carbon quantum dots (LCQDs) modified chitosan carbon aerogel (C-LCDCA). The introduced LCQDs and low carbonization temperature (280 °C) ensured hydrophilic properties while maintaining the three-dimensional porous structure, as well as improved light absorption and photothermal conversion properties. The evaporation rate of C-LCDCA under one sun was 1.71 kg m−2h−1. Interestingly, C-LCDCA promoted the local crystallization of salt crystals and realized the collection. The evaporation performance of the evaporator can be adapted to different evaporation situations by making simple layer adjustments. The optimal C-LCDCA evaporator (4-layer integrated) surpassed the limit of the interfacial evaporation system, with evaporation rate and efficiency up to 2.32 kg m−2h−1 and 113.9 % respectively under one sun, and with strong salt-rejecting (no obvious salt crystallization in 20 wt% brine for 8 h) and excellent self-cleaning ability (0.3 g NaCl re-dissolved back to 15 wt% brine in 15 min). With superior evaporation performance, the condensate obtained by the evaporator in simulated seawater evaporation experiments met the World Health Organization’s drinking water standards, and enabled effective treatment of industrial wastewater containing heavy metal ions (Cr3+, Fe3+, Pb2+, and Ni2+), nanoplastics (500 and 50 nm), and dyes (Rhodamine B, Methyl Orange, and Malachite green). These findings provide new ideas for the preparation of efficient, salt-rejecting, self-cleaning, and environmentally friendly solar evaporators and advance the practical application of sustainable water purification technologies.

Nano-laminated BN modified graphite reinforced unfired MgO–C refractories: Preparation, properties and strengthening mechanism

To solve the problem of deterioration of oxidation resistance and thermal shock resistance caused by low carbonization of MgO–C refractories, nano-laminated BN modified graphite was prepared by the molten salt method to reinforce unfired MgO–C refractories. The findings revealed that the introduction of nano-laminated BN modified graphite significantly improved the mechanical properties. Moreover, the oxidation index of MgO–C refractories with 4 wt% nano-laminated BN modified graphite was 34% lower than that of the unadded sample, and the residual strength after thermal shock was significantly increased by 224%. Furthermore, incorporating nano-laminated BN modified graphite facilitated the formation of columnar Mg2SiO4, octagonal columnar MgAl2O4, and MgO–Mg2SiO4–MgAl2O4–Mg3B2O6 dense layers, thereby contribute to overall performance improvements.

Hybrid hard carbon framework derived from polystyrene bearing distinct molecular crosslinking for enhanced sodium storage

AbstractExploiting high‐performance yet low‐cost hard carbon anodes is crucial to advancing the state‐of‐the‐art sodium‐ion batteries. However, the achievement of superior initial Coulombic efficiency (ICE) and high Na‐storage capacity via low‐temperature carbonization remains challenging due to the presence of tremendous defects with few closed pores. Here, a facile hybrid carbon framework design is proposed from the polystyrene precursor bearing distinct molecular bridges at a low pyrolysis temperature of 800°C via in situ fusion and embedding strategy. This is realized by integrating triazine‐ and carbonyl‐crosslinked polystyrene nanospheres during carbonization. The triazine crosslinking allows in situ fusion of spheres into layered carbon with low defects and abundant closed pores, which serves as a matrix for embedding the well‐retained carbon spheres with nanopores/defects derived from carbonyl crosslinking. Therefore, the hybrid hard carbon with intimate interface showcases synergistic Na ions storage behavior, showing an ICE of 70.2%, a high capacity of 279.3 mAh g−1, and long‐term 500 cycles, superior to carbons from the respective precursor and other reported carbons fabricated under the low carbonization temperature. The present protocol opens new avenues toward low‐cost hard carbon anode materials for high‐performance sodium‐ion batteries.

A Hybrid Real-Time Electricity Pricing Strategy with Carbon Capture, Storage and Trading

During the power system low carbonization process, various policies and technologies for low-carbon have been rapidly developed. Real-time demand side management by energy suppliers based on real-time pricing (RTP) has become a reality via smart meter technology. Motivated by this, an RTP mechanism is used to guide users’ demand response, and the carbon trading regulation (CTR) and carbon capture, storage (CCS) technology are used on the supply side. Through these means, we can reduce carbon emissions from the power system and achieve the goal of carbon neutrality. Furthermore, a game model is used to construct the relationship between the energy supplier and users. Since the energy supplier acts first and then the user make their decision, the leader is the energy supplier and the followers are users. Further, to protect the information privacy of them and independently solve the goals of them, a distributed solution approach combining a differential evolutionary (DE) algorithm and Gurobi solver is developed for finding the equilibrium solution. The proposed model’s economic and environmental benefits are verified and the effectiveness of CCS technology and CTR is accessed via the numerical analysis, what means the proposed strategy can serve as a guide for the system’s low-carbon management.

Standardization and micromechanistic study of tetracycline adsorption by biochar

Modification serves as an excellent approach to enhancing the adsorption performance of biochar for tetracycline. Selective modification further allows the attainment of biochar materials that are not only more efficient but also cost-effective. However, the key structural factors influencing the adsorption of tetracycline by biochar remain unclear at present, hindering the effective guidance for modification strategies. This study established the relationship between carbonization degree and adsorption capacity, constructed a standardized microscopic model for biochar adsorption of tetracycline, and explored potential reaction mechanisms. The results indicated that with increases in the degree of carbonization, the tetracycline adsorption capacity of biochar increased from 16.08 mg L−1 to 98.35 mg L−1. The adsorption energy exhibited a strong correlation with the aromatic condensation of biochar at p ≤ 0.01, with a linear relationship (r2 ≥ 0.94). For low carbonization degrees, the adsorption of tetracycline by biochar was primarily driven by chemical bonds (69.21%) and complemented with electrostatic interactions, weak van der Waals forces or π-π interactions. For high carbonization degrees, the synergistic effects of hydrogen bonding, van der Waals forces, and π-π interactions determined the adsorption of tetracycline on biochar (91.1%). Additionally, larger carbon clusters resulted in stronger and more stable adsorption interactions. Furthermore, carboxyl-functionalized highly carbonized biochar displayed the highest reaction energy of − 1.8370 eV for adsorption of tetracycline through electrostatic interactions. This study suggests that a high degree of aromatic condensation in the carbon structure of biochar is crucial for the efficient adsorption of tetracycline.Graphical