Facile preparation of N/P co-doped mesoporous biochar for efficient removal of methylene blue from aqueous solutions: A 2D-FTIR-COS, adsorption mechanism analysis, and fixed-bed column study
Shisuo Fan , Manquan Zhao , Jiajia Luo , Weicheng Li , Xinru Fan , Na Zhou , Huacheng Xu , Yuanzhi Shi
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引用次数: 0
Abstract
Modification is a common strategy to optimize the physicochemical properties of biochar to reinforce its adsorption efficiency, especially a method that can achieve multiple modification purposes. In this study, rice straw was used as feedstock and ammonium phosphate [(NH4)3PO4] was used as N and P co-modifiers to synthesize modified biochars at various pyrolysis temperatures, and their adsorption properties and mechanisms toward methylene blue (MB) were investigated systematically. The results showed that the specific surface area and aromaticity of biochars increased with the increase in pyrolysis temperature. The (NH4)3PO4 modification endowed modified biochars with developed mesoporous structure, abundant nitrogen and phosphorus functional groups, more graphitic structure, and high ash content. The (NH4)3PO4 modification enhanced the adsorption efficiency of the biochars for MB. Batch adsorption and dynamic fixed-bed experiments showed that NPBC900 ((NH4)3PO4 modified biochar prepared at 900 °C) presented a good adsorption performance for MB, among which Langmuir and pseudo-second-order kinetic models better described the batch adsorption process of NPBC900 for MB, whereas the Thomas, Clark, and Adams-Bohart models better fitted the dynamic adsorption process of NPBC900 for MB. The maximum adsorption capacity of NPBC900 for MB reached 156.36 mg/g. In addition, adsorption of MB on NPBC900 was a spontaneous, endothermic, randomness-enhancing process, and occurred in a wide pH range (3.0–9.0) and in the presence of coexisting ions. The main adsorption mechanisms of NPBC900 for MB removal were pore filling, π–π interaction, hydrogen bonding, complexation, and electrostatic effect. The 2D-FTIR-COS analysis showed that the adsorption mechanisms between MB and NPBC900 followed the order π–π interaction > hydrogen bonding > electrostatic interaction. This research provided new insights into the adsorption mechanisms and practical application of modified biochar for pollutant removal.
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The Journal of Water Process Engineering aims to publish refereed, high-quality research papers with significant novelty and impact in all areas of the engineering of water and wastewater processing . Papers on advanced and novel treatment processes and technologies are particularly welcome. The Journal considers papers in areas such as nanotechnology and biotechnology applications in water, novel oxidation and separation processes, membrane processes (except those for desalination) , catalytic processes for the removal of water contaminants, sustainable processes, water reuse and recycling, water use and wastewater minimization, integrated/hybrid technology, process modeling of water treatment and novel treatment processes. Submissions on the subject of adsorbents, including standard measurements of adsorption kinetics and equilibrium will only be considered if there is a genuine case for novelty and contribution, for example highly novel, sustainable adsorbents and their use: papers on activated carbon-type materials derived from natural matter, or surfactant-modified clays and related minerals, would not fulfil this criterion. The Journal particularly welcomes contributions involving environmentally, economically and socially sustainable technology for water treatment, including those which are energy-efficient, with minimal or no chemical consumption, and capable of water recycling and reuse that minimizes the direct disposal of wastewater to the aquatic environment. Papers that describe novel ideas for solving issues related to water quality and availability are also welcome, as are those that show the transfer of techniques from other disciplines. The Journal will consider papers dealing with processes for various water matrices including drinking water (except desalination), domestic, urban and industrial wastewaters, in addition to their residues. It is expected that the journal will be of particular relevance to chemical and process engineers working in the field. The Journal welcomes Full Text papers, Short Communications, State-of-the-Art Reviews and Letters to Editors and Case Studies
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