Elsevier

Chemosphere

Volume 246, May 2020, 125757
Chemosphere

Adsorption behavior of dyes from an aqueous solution onto composite magnetic lignin adsorbent

https://doi.org/10.1016/j.chemosphere.2019.125757Get rights and content

Highlights

  • The low-cost calcium lignosulfonate waste was reused.

  • The magnetic lignin-based adsorbent was prepared using Fe3O4 as magnetic source.

  • The FCS successfully acted as excellent adsorbent for the removal of anionic azo dyes.

  • The synthesis of FCS can be recycled.

Abstract

Magnetic lignosulfonate functional materials that were known to remove several types of dye from water effectively were prepared. The surface of an iron (II,III) oxide (Fe3O4) sample was coated with a layer of organic carbon, and magnetic lignosulfonate (FCS) was synthesised by a crosslinking agent. The morphology, structure, stability and magnetic properties of the materials were characterised by various testing methods. Under experimental conditions, the solution’s acidity, alkalinity, contact time, temperature, desorption and dye concentration were measured. The experimental results show that the material reached the highest adsorption capacity at pH = 7. In addition, the adsorption data was similar to that of a single layer, Langmuir adsorption model. The maximum adsorption capacities were 198.24 mg g−1 (Congo Red) and 192.51 mg g−1 (Titan Yellow), respectively. Based on its desorption performance, the material had good recyclability. Therefore, these studies could be used in wastewater treatment. Hopefully, the proposed magnetic composites will inspire more scholars to investigate solutions to the problem of contaminated water resources.

Introduction

Efficient treatment of industrial wastewater polluted by organic dyes is a major and persistent environmental problem. Dyes generally have some complex organic compounds, and these are toxic (Yagub et al., 2014, Yang et al., 2018, Crini, 2006). They are used for colouring textiles, paper, leather, food, polymers and cosmetics, as well as for printing and dye manufacturing. The improper treatment of dyes could be disastrous for the environment (Piccin et al., 2016). Since organic dyes are generally not readily biodegradable, dyes must be removed from industrial wastewater using appropriate water treatment techniques prior to discharge into the environment (Ma et al., 2015, Colombo et al., 2017, Wu et al., 2019, Banerjee et al., 2019). While organic dyes can be removed from the aqueous phase using a variety of processing techniques, including membrane filtration and ion exchange, one of the most effective, widely-used methods for removing dyes from wastewater is adsorption. It is an environmentally-friendly method for treating dye pollution (Al-Ghouti et al., 2016, Shabandokht et al., 2016, Dominguez-Robles et al., 2018, Qiu et al., 2017, Satilmis and Budd, 2017). It has many advantages, such as high efficiency, low cost and little impact, so it is widely used to treat dye pollution (Huang et al., 2017). However, separation after adsorption is a defect in the adsorption process that limits its use. Magnetic polymers are a new type of composite material developed in recent years. Compared with non-magnetic materials, they have the advantage of easy separation (Miao et al., 2019, Zhou et al., 2018, Siyasukh et al., 2018, Zeng et al., 2016). Nowadays, composite magnetic materials are generally organic and inorganic, mainly iron, cobalt, nickel, their alloys and the oxides of other iron-containing elements. When selecting magnetic materials for adsorbents, two important factors are stable performance and low biological toxicity. Iron (II,III) oxide (Fe3O4) has these advantages, so it is widely used in composites (Siddiqui and Chaudhry, 2019). Natural polymers have been widely used because of the rise of composite materials (Fleischmann et al., 2015, Figueiredo et al., 2018, Minnocci et al., 2018). Lignosulfonate is a paper industry by-product, with little or no application elsewhere, resulting in high quantities of waste and potential pollution (Figueiredo et al., 2018, Rębiś et al., 2016). However, when lignin, cellulose and their derivatives are added to create composites, the biodegradability, multi-functionality and biocompatibility of the resultant materials improved immensely. Lignosulfonate adsorbents can not only use lignosulfonates effectively by modifying and adding magnetic materials, but also effectively separate and re-use them after adsorption (Zhang et al., 2017, Vakili et al., 2018, Arel, 2017, Jha and Kumar, 2018, Megiatto et al., 2016, Modrzejewska-Sikorska et al., 2017, Ye et al., 2016, Ye et al., 2017, Ling et al., 2011, Gupta and Suhas, 2009).

Titan Yellow (TY) and Congo Red (CR) are two of the most commonly used dyes in industry. Large-scale use of dyes produces large amounts of wastewater. This study involves the synthesis of magnetic materials, using sodium lignosulfonate as a main component, in the adsorption of two azo dyes. The adsorption process was explored under different conditions, and the adsorption mechanism was studied using different models.

Section snippets

Materials

Iron(III) Chloride (FeCl3) (Shanghai Aladdin Biochemical Technology Co. Ltd.); glucose (Tianjin Fu Chen Co. Ltd.); sodium lignosulfonate (Sinopharm Chemical Reagent Co. Ltd.); sodium acetate (Shanghai Aladdin Biochemical Technology Co. Ltd.); ethylene glycol (Sinopharm Chemical Reagent Co. Ltd.); triethylene tetramine (Sinopharm Chemical Reagent Co. Ltd.); TY (Shanghai Aladdin Biochemical Technology Co. Ltd.); and CR (Shanghai Aladdin Biochemical Technology Co. Ltd.). Other reagents were

Characterisation of FCS adsorbent

It can be seen from (A) and (B), in Fig. 1, that Fe3O4 is spherical with a rough surface, and the FC surface is relatively smooth. The reason for this phenomenon is that, on the FC, carbon is coated on the Fe3O4 surface. This explanation is also demonstrated by (D) and (E). In Fig. 1 (D), the Fe3O4 is agglomerated and has a darker colour, while in (E), due to carbon coating on the Fe3O4 surface, the FC’s transmission colour is shallow. In Fig. 1 (C), the FCS is layered and overlapped. This is a

Conclusions

In this study, a composite based on Fe3O4 and lignosulfonate was developed as an effective dye adsorbent. Factors affecting its adsorption performance, such as the dosage, the pH of the solution, the initial concentration of the dye, the contact time and the temperature, were investigated. An adsorption isotherm study of the two dyes showed that the experimental data is similar to the Langmuir isotherm model. The kinetic results indicated that the adsorption was most likely suitable for the

Author contributions

Authors:Lishuang Hu*, Chunyu Guang, Yang Liu, Zengqiang Su, Shida Gong and Yajing Yao. Lishuang Hu developed the idea for the study; Chunyu Guang and Yang Liu carry out experiments; All authors analysed the data and were involved in writing the manuscript.

Declaration of competing interest

None.

Acknowledgments

This work was supported by Scientific and Technologial Innovation Programs of Higher Education Institutions in Shanxi (STIP, 2019L0517).

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

References (37)

Cited by (83)

  • Application of lignin adsorbent in wastewater Treatment: A review

    2022, Separation and Purification Technology
View all citing articles on Scopus
View full text