Development of Agro-Based Engineered Biochars for Low Concentration Nitrate Adsorption: Modification Selection, Performance, Factors, Mechanism, and Reliability

IF 3.8 4区环境科学与生态学 Q2 ENVIRONMENTAL SCIENCES

Water, Air, & Soil Pollution Pub Date : 2025-04-21 DOI:10.1007/s11270-025-07967-3

Wenjia Han, Ai Chen, Zhuocan Li, Rong Zhou, Kai Zhang, Wei Zhao, Xiaotao Bi, Xiali Zhang

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引用次数: 0

Abstract

This study aimed to develop agro-based engineered biochars for adsorbing low concentration nitrate with economic and effective characteristics. Two kinds of wheat or corn-straw based biochars were prepared at different pyrolysis temperatures using the acid/iron modification method. The performance of adsorption and desorption, mechanism (adsorption model, biochar morphology, zeta potential), influencing factors (pH, co-existence of anions and organic matter) and stability were comprehensively evaluated. The results showed that the modification by HCl impregnation for corn straw-based biochars (CH500) or HCl-FeCl₃ for wheat-straw based biochar pyrolyzed at 500 °C (WFe500) could reach a NO₃⁻ removal efficiency of 85–91% within 24 - 48 h at a low concentration of 20 mg N L⁻¹. The maximum adsorption capacity (Q_m) from Langmuir model for the CH500 (1958 mg kg⁻¹) was 20% greater than that of WFe500 (1651 mg kg ⁻¹). After the kinetic adsorption reached the equilibrium, there was no clear desorption by DI water. The pH had no significant effect on the adsorption, and the adsorption efficiency of NO₃⁻ could be kept at ~ 60% under the co-existence of anions as well. After acid or iron modification, polarity index of H/C further decreased, and the index of (O + N)/C or O/C further increased. The zeta potential (ζ), the BET surface area and pore volume of CH500 and WFe500 also increased. It was suggested that the modification increased the positive charge loads of H⁺ and Fe³⁺ on the biochar surface, which enhanced polarity and electrostatic attractions and led to increased effective contacts between the biochar and low concentration NO₃⁻. The NO₃⁻ accumulated at the charge sites on the surface and inside the biochar via electrostatic attraction could replace other anion previously fixed on the biochar (such as Cl⁻ loaded by modification) via ion exchange. The increased volumes/areas of internal pores by the modification were crucial for adsorption and retention of NO₃⁻ ions after the effective contact. The modification method, pollutant characteristics and biochar feed stock characteristics should be considered together as primary influencing factors for preparing high performance biochar.

Graphical Abstract

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农用低浓度硝酸盐吸附工程生物炭的开发：改性选择、性能、影响因素、机理和可靠性

本研究旨在开发具有经济、有效吸附低浓度硝酸盐特性的农用工程生物炭。采用酸/铁改性法在不同热解温度下制备了小麦基和玉米秸秆基两种生物炭。综合评价了吸附解吸性能、机理（吸附模式、生物炭形态、zeta电位）、影响因素（pH、阴离子与有机物共存）和稳定性。结果表明，在低浓度20 mg N L−1条件下，HCl浸渍改性玉米秸秆基生物炭（CH500）或HCl- fecl3改性500℃热解小麦秸秆基生物炭（WFe500），在24 ~ 48 h内NO3−去除率可达85 ~ 91%。Langmuir模型对CH500 （1958 mg kg−1）的最大吸附量（Qm）比WFe500 （1651 mg kg−1）大20%。动力学吸附达到平衡后，无明显的DI水解吸现象。pH对NO3−的吸附无显著影响，在阴离子共存的情况下，NO3−的吸附效率也可保持在60%左右。经酸或铁改性后，H/C极性指数进一步降低，(O + N)/C或O/C极性指数进一步升高。CH500和WFe500的ζ电位（ζ）、BET比表面积和孔容均有所增加。结果表明，改性提高了生物炭表面H+和Fe3+的正电荷负荷，增强了极性和静电吸引力，增加了生物炭与低浓度NO3−的有效接触。通过静电吸引在生物炭表面和内部电荷位点积累的NO3−可以通过离子交换取代先前固定在生物炭上的其他阴离子（如改性负载的Cl−）。改性后的内部孔隙体积/面积的增加对有效接触后NO3−离子的吸附和保留至关重要。改性方法、污染物特性和生物炭原料特性是制备高性能生物炭的主要影响因素。图形抽象

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来源期刊

Water, Air, & Soil Pollution 环境科学-环境科学

CiteScore

4.50

自引率

6.90%

发文量

448

审稿时长

2.6 months

期刊介绍： Water, Air, & Soil Pollution is an international, interdisciplinary journal on all aspects of pollution and solutions to pollution in the biosphere. This includes chemical, physical and biological processes affecting flora, fauna, water, air and soil in relation to environmental pollution. Because of its scope, the subject areas are diverse and include all aspects of pollution sources, transport, deposition, accumulation, acid precipitation, atmospheric pollution, metals, aquatic pollution including marine pollution and ground water, waste water, pesticides, soil pollution, sewage, sediment pollution, forestry pollution, effects of pollutants on humans, vegetation, fish, aquatic species, micro-organisms, and animals, environmental and molecular toxicology applied to pollution research, biosensors, global and climate change, ecological implications of pollution and pollution models. Water, Air, & Soil Pollution also publishes manuscripts on novel methods used in the study of environmental pollutants, environmental toxicology, environmental biology, novel environmental engineering related to pollution, biodiversity as influenced by pollution, novel environmental biotechnology as applied to pollution (e.g. bioremediation), environmental modelling and biorestoration of polluted environments. Articles should not be submitted that are of local interest only and do not advance international knowledge in environmental pollution and solutions to pollution. Articles that simply replicate known knowledge or techniques while researching a local pollution problem will normally be rejected without review. Submitted articles must have up-to-date references, employ the correct experimental replication and statistical analysis, where needed and contain a significant contribution to new knowledge. The publishing and editorial team sincerely appreciate your cooperation. Water, Air, & Soil Pollution publishes research papers; review articles; mini-reviews; and book reviews.