Study of mechanism of p-dinitrobenzene adsorption by modified bentonites when water purification in static conditions

Q3 Environmental Science

Water and Ecology Pub Date : 2020-06-01 DOI:10.23968/2305-3488.2020.25.2.3-11

O. Atamanova, E. Tikhomirova, M. Istrashkina, A. A. Podoksenov

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引用次数: 1

Abstract

Introduction. The paper provides a rationale for bentonite modification with organic substances to increase its adsorption capacity. The purpose of studying the adsorption mechanism of p-dinitrobenzene on bentonite modified by various methods is to determine such modifications of bentonite that allow for the most efficient removal of this toxic nitro compound from industrial wastewater. Methods. The authors analyzed four variants of bentonite adsorbent: unmodified granular bentonite; carbon nanotube (CNT) modified bentonite after heat treatment at 550 °C; glycerin modified bentonite after heat treatment at 550°C; glycerin and CNT modified bentonite after heat treatment at 550 °C. To determine the type of adsorption of p-dinitrobenzene on the studied sorption materials, the Dubinin– Radushkevich method was used. Results. Basic adsorption characteristics of the four indicated modifications of bentonite with respect to p-dinitrobenzene under static conditions were experimentally obtained. CNT modified bentonite showed the best adsorption characteristics: СОЕ = 1.56 mEq/g; Kd = 0.14 mg/dm3; S = 83.57 %. The constructed isotherms for adsorption of p-dinitrobenzene on modified and unmodified bentonites under static conditions confirmed that CNT modified bentonite after heat treatment at 550 °C has the best adsorption capacity. Unmodified bentonite showed the weakest adsorption capacity. The derived adsorption equations demonstrated that this process can be most accurately described by the Langmuir isotherm. With changes in the experimental temperature from 20 to 60 °C, the values of mean free energy E of adsorption of p-dinitrobenzene vary in the range of 11–20 kJ/mol. Thus, chemisorption is present in the process of adsorption of p-dinitrobenzene by the studied sorption materials.

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静态条件下改性膨润土对二硝基苯的吸附机理研究

介绍本文提出了用有机物改性膨润土以提高其吸附能力的基本原理。研究对二硝基苯在用各种方法改性的膨润土上的吸附机理的目的是确定膨润土的改性，以最有效地去除工业废水中的这种有毒硝基化合物。方法。作者分析了膨润土吸附剂的四种变体：未改性颗粒膨润土；550°C热处理后的碳纳米管改性膨润土；甘油改性膨润土经550°C热处理后；甘油和CNT改性膨润土。为了确定对二硝基苯在所研究的吸附材料上的吸附类型，使用了Dubinin–Radushkevich方法。后果实验获得了四种改性膨润土在静态条件下对对二硝基苯的基本吸附特性。CNT改性膨润土表现出最佳的吸附特性：СОε=1.56mEq/g；Kd=0.14mg/dm3；S=83.57%。在静态条件下构建的对二硝基苯在改性和未改性膨润土上的吸附等温线证实，经550°C热处理的CNT改性膨膨润土具有最佳的吸附能力。未改性膨润土的吸附能力最弱。导出的吸附方程表明，Langmuir等温线可以最准确地描述这一过程。随着实验温度从20°C到60°C的变化，对二硝基苯吸附的平均自由能E值在11–20 kJ/mol的范围内变化。因此，所研究的吸附材料在吸附对二硝基苯的过程中存在化学吸附。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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Water and Ecology Environmental Science-Ecology

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期刊介绍： The scientific and technical journal for experts in the sphere of water supply, water disposal, waste-water treatment and ecology. Published since 1999. Regular columns include communal and industrial water supply; water preparation; treatment of domestic and industrial waste; equipment; materials; use; maintenance. The journal’s main goal is to provide a wide range of professionals with the information about the latest innovative developments and tendencies. The journal deals with issues on water supply, water disposal, waste-water treatment and ecology.