Elsevier

Bioresource Technology

Volume 259, July 2018, Pages 104-110
Bioresource Technology

Highly efficient adsorption of dyes by biochar derived from pigments-extracted macroalgae pyrolyzed at different temperature

https://doi.org/10.1016/j.biortech.2018.02.094Get rights and content

Highlights

  • Macroalgae residue is promising raw material for producing biochar.

  • Biochar derived from pigments-extracted macroalgae is a promising adsorbent.

  • The malachite green adsorption capacity of MDBC800 is 5306.2 mg/g.

Abstract

Biochar is known to efficiently adsorb dyes from wastewater. In this study, biochar was derived from macroalgae residue by pyrolysis, and the influence of varying temperature (from 400 °C to 800 °C) on biochar characteristics was investigated. Among the biochar samples tested, macroalgae-derived biochar possessing highly porous structure, special surface chemical behavior and high thermal stability was found to be efficient in removing malachite green, crystal violet and Congo red. The biochar derived by pyrolysis at 800 °C showed the highest adsorption capacity for malachite green (5306.2 mg g−1). In this study, the transformation of microalgae residue into a highly efficient dye adsorbent is a promising procedure for economic and environmental protection.

Introduction

Algae are promising sources of nutrition and biofuel because of their pigment and lipid content. Moreover, they can be cultivated in wastewater, do not require fertile land, do not compete with food crops, and reduce greenhouse gases from the environment (Chen et al., 2017). Researches have recently been focusing on both nutritional and pharmaceutical applications of algal pigments. However, the cost of algae cultivation and harvesting is high, which limits the downstream application of biodiesel production. Numerous studies indicate that residual algal biomass can be used as a substrate for bioethanol and biogas, as well as for animal/poultry/fish feed and fertilizer (Rashid et al., 2013). Since the cultivation of macroalgae is relative effortless, and the biochar derived from this source has a high absorbability of pollutants, macroalgae-derived biochar (MDBC) is drawing more and more attention as a promising potential candidate of low-cost adsorbent. Notably, MDBC can efficiently remove both organic and inorganic environmental contaminants because of its high surface area, stable structure, negative surface charge, high ion exchange capacity and the presence of various value-added surface functional groups (Ho et al., 2017). Jung et al. (2016) also demonstrated that MDBC was a good fertilizer after adsorbing phosphate. Zheng et al. (2017) suggested that biochar from Chlorella sp. Cha-01 has a high potential to remove p-nitrophenols in wastewater treatment or emergency water pollution control. Nautiyal et al. (2016) utilized the residual biomass of Spirulina platensis to remove up to 82.6% of Congo red (CR) dye.

Dye-containing wastewater is one of the most serious water pollution issues in textile, paper, plastic, leather and other industries. It is difficult to estimate the discharge of various dyes in the environment accurately (Lee and Pavlostathis, 2004). Most dyes not only destroy aquatic organisms but also harm humans because of carcinogenic, mutagenic and teratogenic properties and respiratory toxicity (Luan et al., 2016, Sharifpour et al., 2018). Malachite green (MG) is widely applied in the paper and spinning industries and used for biological control. Crystal violet (CV) is always applied for textile dyeing as a biological stain (Saeed et al., 2010). CR is a textile industry released dye, almost 15% of which flows into wastewater (Chatterjee et al., 2010). Therefore, it is necessary to find effective ways to remove dyes from effluents. The most common methods of removing dyes from industrial effluents are biological oxidation, flocculation, chemical precipitation and activated carbon adsorption. Being simple and effective, the adsorption treatment method is a promising way to remove dyes and organic compounds from aqueous effluents (Fontoura et al., 2017). To date, amounts of studies focus on the dye removal by biochar, but there is still no study on the dye removal by the biochar from pigments-extraction macroalgae.

The aim of this work was to investigate whether MDBC can be efficiently used for functional biochar production, as well as for the identification of surface chemical behavior and the definition of dye sorption mechanisms. In this study, MDBC was initially obtained through pyrolysis. The capacity of MDBC for removal of various dyes, such as MG, CV and CR, was investigated at different pyrolysis temperatures. The adsorption kinetics, sorption isotherm and corresponding dye removal mechanisms were studied under optimal conditions. In addition, physicochemical properties and adsorption mechanisms of MDBC before and after adsorption were studied by analyzing the change in surface chemical behavior through elemental analysis (EA), scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), fourier transform infrared spectroscopy (FTIR) and Brunauer-Emmett-Teller (BET). The knowledge created from this study can be used to conclude whether biochar produced from macroalgae is an efficient adsorbent for dyes, which makes the proposed method a promising way to treat macroalgae residue.

Section snippets

Macroalgae preparation

Ulothrix zonata algae from south of Taiwan, Pingtung, were collected after being rinsed and extracted with distilled water at 60 °C for 4–5 h to extract fucoxanthin. Then algae filaments were used as an adsorbent in this research after being dried for 48 h at 40 °C. Chlorophyll and carotenoids were extracted from macroalgae biomass which was mixed with acetone by ultrasonic destruction for 5 times, and 20 min for each time. Finally, the macroalgae residue was dried for 12 h at 105 °C.

Preparation and characterization of macroalgae-derived biochar

MDBC

Elemental composition and surface morphology of macroalgae-derived biochar

To analyze the chemical process of the adsorption, the main characteristics of MDBC produced at three temperatures (Table 1). The biochar yield percentage for MDBC was 46.2% at 400 °C, but declined to 22.6% at 800 °C. The amount of surface functional group elements, e.g. H, O and N, were reduced because volatile matter was vanished with increasing pyrolysis temperature (Table 1). The molar ratios of H/C and O/C are the main parameters for carbonization degree, which is generally used to

Conclusion

In this study, physicochemical characteristics of MDBC annealed at different pyrolysis temperatures were evaluated by analyzing the chemical behavior of MDBC surface. MDBC800 was found to be the most efficient adsorbent for dyes including MG, CV and CR. The Freundlich isotherm and pseudo-second-order model describe the dye adsorption isotherms and kinetics on MDBC800, respectively. The highest dye adsorption capacity, especially for MG, was 5306.2 mg g−1 by MDBC800. MDBC can serve as a

Acknowledgements

This work was supported by the State Key Laboratory of Urban Water Resource and Environment (Harbin Institute of Technology) (No. 2016TS07). This work was also supported by the Project of Thousand Youth Talents.

References (44)

  • Y.S. Ho et al.

    Kinetic models for the sorption of dye from aqueous solution by wood

    Process. Saf. Environ.

    (1998)
  • J. Jin et al.

    Influence of pyrolysis temperature on properties and environmental safety of heavy metals in biochars derived from municipal sewage sludge

    J. Hazard. Mater.

    (2016)
  • K.W. Jung et al.

    Characteristics of biochar derived from marine macroalgae and fabrication of granular biochar by entrapment in calcium-alginate beads for phosphate removal from aqueous solution

    Bioresour. Technol.

    (2016)
  • Y.H. Lee et al.

    Decolorization and toxicity of reactive anthraquinone textile dyes under methanogenic conditions

    Water. Res.

    (2004)
  • X.P. Luo et al.

    Adsorption of methylene blue and malachite green from aqueous solution by sulfonic acid group modified MIL-101

    Microporous Mesoporous Mater.

    (2017)
  • P. Nautiyal et al.

    Adsorptive removal of dye using biochar derived from residual algae after in-situ transesterification: alternate use of waste of biodiesel industry

    J. Environ. Manage.

    (2016)
  • L.S. Oliveira et al.

    Evaluation of untreated coffee husks as potential biosorbents for treatment of dye contaminated waters

    J. Hazard. Mater.

    (2008)
  • N. Rashid et al.

    Recycling and reuse of spent microalgal biomass for sustainable biofuels

    BioChem. Eng. J.

    (2013)
  • A. Saeed et al.

    Application potential of grapefruit peel as dye sorbent: kinetics, equilibrium and mechanism of crystal violet adsorption

    J. Hazard. Mater.

    (2010)
  • P. Saha et al.

    Insight into adsorption equilibrium, kinetics and thermodynamics of Malachite Green onto clayey soil of Indian origin

    Chem. Eng. J.

    (2010)
  • D.D. Sewu et al.

    Highly efficient adsorption of cationic dye by biochar produced with Korean cabbage waste

    Bioresour. Technol.

    (2017)
  • E. Sharifpour et al.

    Isotherms and kinetic study of ultrasound-assisted adsorption of malachite green and Pb2+ ions from aqueous samples by copper sulfide nanorods loaded on activated carbon: experimental design optimization

    Ultrason. Sonochem.

    (2018)
  • Cited by (222)

    View all citing articles on Scopus
    View full text