Elsevier

Bioresource Technology

Volume 227, March 2017, Pages 359-372
Bioresource Technology

Review
Biochar as potential sustainable precursors for activated carbon production: Multiple applications in environmental protection and energy storage

https://doi.org/10.1016/j.biortech.2016.12.083Get rights and content

Highlights

  • Biochars are potential sustainable precursors for activated carbon production.

  • Physical activation and chemical activation are applied in the production process.

  • Production parameters affect the properties of resultant activated carbon.

  • Multiple applications in environmental protection and energy storage are reviewed.

  • Future perspectives about biochar activation and applications are highlighted.

Abstract

There is a growing interest of the scientific community on production of activated carbon using biochar as potential sustainable precursors pyrolyzed from biomass wastes. Physical activation and chemical activation are the main methods applied in the activation process. These methods could have significantly beneficial effects on biochar chemical/physical properties, which make it suitable for multiple applications including water pollution treatment, CO2 capture, and energy storage. The feedstock with different compositions, pyrolysis conditions and activation parameters of biochar have significant influences on the properties of resultant activated carbon. Compared with traditional activated carbon, activated biochar appears to be a new potential cost-effective and environmentally-friendly carbon materials with great application prospect in many fields. This review not only summarizes information from the current analysis of activated biochar and their multiple applications for further optimization and understanding, but also offers new directions for development of activated biochar.

Introduction

Activated carbon is the carbonaceous material known as its large specific surface area, superior porosity, high physicochemical-stability, and excellent surface reactivity, which is widely employed as functional materials for various applications (Delgado et al., 2012, Sevilla and Mokaya, 2014, Shafeeyan et al., 2010). The commonly used feedstocks for traditional activated carbon production are wood, coal, petroleum residues, peat, lignite and polymers, which are very expensive and non-renewable (Chen et al., 2011). Therefore, many researchers have been focusing on preparing activated carbon using low-cost and sustainable alternative precursors, including agricultural residues (rice husk, corn straw, bagasse etc.) and solid wastes (sludge, food waste, garden waste etc.) (Chen et al., 2011, Yahya et al., 2015). Producing activated carbon from waste and by-products have gained attention since availability of low-cost precursors is necessary for the economic feasibility of large scale activated carbon production.

Recently, much attention has also been focused on the application of these biomass resources for biochar production via various thermochemical processes under oxygen-limited conditions and at relatively low temperatures (<700 °C), including pyrolysis, hydrothermal carbonization, flash carbonization, and gasification (Meyer et al., 2011). Considerable studies have highlighted the benefits of using biochar in terms of carbon sequestration, soil amendment, soil productivity improvement (Manyà, 2012, Sohi, 2012) and pollution control (Ahmad et al., 2014, Mohan et al., 2014, Tan et al., 2015). In addition, the thermochemical treatment of biomass has energy recovery potential, which can generate biofuels and syngas accompanied with biochar production (Manyà, 2012). The resultant biochar usually exhibit porous structure, maintained surface functional groups and mineral components due to the removal of the moisture and the volatile matter contents of the biomass by thermal treatment (Liu et al., 2015). These favorable properties lead to high reactivity of biochar, and hence, make it possible to be used as an alternative carbon material.

However, the applications of biochar in different fields are also restricted due to its limited functionalities, inherited from the feedstock after thermochemical treatment (Tan et al., 2016b). For instance, the un-activated biochar usually shows relatively lower pore properties (especially for micropore volume), which restricts its ability in CO2 capture and energy storage. In addition, the raw biochar has limited ability to adsorb various contaminants (Nair and Vinu, 2016, Yao et al., 2013), particularly for high concentrations of polluted water. Therefore, there is a growing interest of the scientific community on physical and chemical activation of biochar for expending its applications in various areas by improving its chemical/physical properties in the past few years (Ahmed et al., 2016b, Rajapaksha et al., 2016, Tan et al., 2016b). Biochar has been used as a renewable and low-cost precursor for activated carbon production. Globally, the mean price for biochar was $2.65 kg−1, which was highly variable depending on the origin of biochar production sites and ranged from as low as $0.09 kg−1 (Philippines) to $8.85 kg−1 (UK) (Ahmed et al., 2016a). Activated biochar appears to be a new potential cost-effective and environmentally-friendly carbon materials with great application prospect in many fields. Compared with traditional activated carbon, the main advantage of activated biochar is that the feedstocks of biochar production are abundant and low-cost, which mainly obtained from agricultural biomass and solid waste (Table S1) (Tan et al., 2015). The performances of activated biochar applied in various fields have also been reported to be equivalent to or even higher than that of commercial activated carbon and other much more expensive materials such as CNTs and graphene (Angın et al., 2013, Dehkhoda et al., 2014, Jung et al., 2015b, Nguyen and Lee, 2016).

According to the above-explained considerations, the production of biochar from low-cost and sustainable biomass appears to be a very attractive alternative precursor for activated carbon production, which integrates carbon sequestration and renewable energy generation into multiple applications including water pollution treatment, CO2 capture, and energy storage. The purpose of the current review is to review and summarize recent information concerning physical and chemical activation of biochar and their effects on the properties of resultant activated carbon. The influence of these activation methods on the water pollution treatment using activated biochar and the mechanisms of improved adsorption for various contaminants are discussed. In addition, the application of activated biochar for CO2 capture, and energy storage are also reviewed. Furthermore, knowledge gaps and future research needs that exist in the activation and application of activated carbon produced from biochar are highlighted.

Section snippets

Physical activation

Recently, many researches utilize physical methods for biochar activation, which could optimize surface structure of biochar. Significant physical changes in surface area, pore volume, and pore structures of biochar may be achieved by means of physical activations, which are the important parameters for biochar applications. In addition, physical activation may not only change the porosity of biochar but also affect its surface chemical properties (surface functional groups, hydrophobicity and

Application for water pollution treatment

As discussed above, physical and chemical activation could have significantly beneficial effects on biochar chemical/physical properties, including increasing biochar surface areas, improving pore structures, adding surface functional groups, and changing the hydrophobicity of biochar surface. These changes could result in the enhancement of adsorption ability of biochar for various contaminants (Table 1). As shown in the Tables 1 and S4, in most cases, physical and chemical activation usually

Application for CO2 capture

The reduction of anthropogenic CO2 release into the atmosphere has been recognized as the crucial matter due to its huge contribution to global climate change (Nasri et al., 2014, Toro-Molina et al., 2012). Adsorption is considered as a promising method for CO2 separation and the surface physical and chemical properties of adsorbent play a critical role during the adsorption process (Zhang et al., 2014a). Biochar produced from biomass waste followed by activation usually showed high surface

Application for energy storage

In addition to these applications mentioned above, biochar-based activated carbons have also been used in energy storage fields. For example, activated biochar have been employed as electrode materials for supercapacitors or as porous matrix to host active substances for cathodes (Table 2, Table 5).

Future perspectives

Thus it can be seen that, activated biochar appears to be a new potential cost-effective and environmentally-friendly carbon material with great application prospect in many fields. Despite recent researches on production and application of activated biochar in multiple areas are increasing, a number of research gaps still exist (Fig. 1). To close these knowledge gaps, the following recommendations are suggested:

  • (i)

    The feedstock with different compositions, production conditions and activation

Conclusions

This review presents a summary of biochar activation and the multiple applications of resultant activated carbon. The different functions of activation methods on the specific properties of biochar result in the different adsorption ability of activated biochar for various contaminants. The abundance, applicable physical/chemical properties, and ease of processability of activated biochar make it suitable to be employed as cost-effective and environmentally-friendly material for CO2 capture and

Acknowledgements

The authors would like to thank financial support from the National Natural Science Foundation of China (Grant Nos. 51609268, 41271332, 51521006, 41301339, and 51608208), and the Hunan Provincial Innovation Foundation for Postgraduate (Grant Nos. CX2015B090 and CX2015B092).

References (99)

  • A.M. Dehkhoda et al.

    A novel method to tailor the porous structure of KOH-activated biochar and its application in capacitive deionization and energy storage

    Biomass Bioenergy

    (2016)
  • L.F. Delgado et al.

    The removal of endocrine disrupting compounds, pharmaceutically activated compounds and cyanobacterial toxins during drinking water preparation using activated carbon—a review

    Sci. Total Environ.

    (2012)
  • H. Demiral et al.

    Production of activated carbon from olive bagasse by physical activation

    Chem. Eng. Res. Des.

    (2011)
  • Z.H. Ding et al.

    Removal of lead, copper, cadmium, zinc, and nickel from aqueous solutions by alkali-modified biochar: batch and column tests

    J. Ind. Eng. Chem.

    (2016)
  • E.N. El Qada et al.

    Adsorption of Methylene Blue onto activated carbon produced from steam activated bituminous coal: a study of equilibrium adsorption isotherm

    Chem. Eng. J.

    (2006)
  • A. Elmouwahidi et al.

    Activated carbons from KOH-activation of argan (Argania spinosa) seed shells as supercapacitor electrodes

    Bioresour. Technol.

    (2012)
  • R. Farma et al.

    Preparation of highly porous binderless activated carbon electrodes from fibres of oil palm empty fruit bunches for application in supercapacitors

    Bioresour. Technol.

    (2013)
  • K.F. Fu et al.

    Preparation, characterization and application of lignin-based activated carbon from black liquor lignin by steam activation

    Chem. Eng. J.

    (2013)
  • M. Galhetas et al.

    Chars from gasification of coal and pine activated with K2CO3: acetaminophen and caffeine adsorption from aqueous solutions

    J. Colloid Interface Sci.

    (2014)
  • C. Guizani et al.

    Effects of CO2 on biomass fast pyrolysis: reaction rate, gas yields and char reactive properties

    Fuel

    (2014)
  • R.K. Gupta et al.

    Biochar activated by oxygen plasma for supercapacitors

    J. Power Sources

    (2015)
  • L. Hadjittofi et al.

    Activated biochar derived from cactus fibres–preparation, characterization and application on Cu (II) removal from aqueous solutions

    Bioresour. Technol.

    (2014)
  • W. Hao et al.

    Activated carbons prepared from hydrothermally carbonized waste biomass used as adsorbents for CO2

    Appl. Energy

    (2013)
  • I. Herath et al.

    Mechanistic modeling of glyphosate interaction with rice husk derived engineered biochar

    Micropor. Mesopor. Mat.

    (2016)
  • R. Hoseinzadeh Hesas et al.

    The effects of a microwave heating method on the production of activated carbon from agricultural waste: a review

    J. Anal. Appl. Pyrol.

    (2013)
  • U. Iriarte-Velasco et al.

    An insight into the reactions occurring during the chemical activation of bone char

    Chem. Eng. J.

    (2014)
  • J. Jiang et al.

    Highly ordered macroporous woody biochar with ultra-high carbon content as supercapacitor electrodes

    Electrochim. Acta

    (2013)
  • H. Jin et al.

    Carbon materials from high ash biochar for supercapacitor and improvement of capacitance with HNO3 surface oxidation

    J. Power Sources

    (2013)
  • H.M. Jin et al.

    Biochar pyrolytically produced from municipal solid wastes for aqueous As (V) removal: adsorption property and its improvement with KOH activation

    Bioresour. Technol.

    (2014)
  • S.H. Jung et al.

    Production of biochars by intermediate pyrolysis and activated carbons from oak by three activation methods using CO2

    J. AnaL. App. Pyrol.

    (2014)
  • C. Jung et al.

    Competitive adsorption of selected non-steroidal anti-inflammatory drugs on activated biochars: experimental and molecular modeling study

    Chem. Eng. J.

    (2015)
  • C. Jung et al.

    Removal of humic and tannic acids by adsorption–coagulation combined systems with activated biochar

    J. Hazard. Mater.

    (2015)
  • E.E. Kwon et al.

    Energy recovery from microalgal biomass via enhanced thermo-chemical process

    Biomass Bioenergy

    (2014)
  • Y. Li et al.

    Biochar as a renewable source for high-performance CO2 sorbent

    Carbon

    (2016)
  • I.M. Lima et al.

    Influence of post-treatment strategies on the properties of activated chars from broiler manure

    Chemosphere

    (2014)
  • M. Machida et al.

    Prediction of simultaneous adsorption of Cu(II) and Pb(II) onto activated carbon by conventional Langmuir type equations

    J. Hazard. Mater.

    (2005)
  • D.K. Mahmoud et al.

    Batch adsorption of basic dye using acid treated kenaf fibre char: equilibrium, kinetic and thermodynamic studies

    Chem. Eng. J.

    (2012)
  • D. Mohan et al.

    Organic and inorganic contaminants removal from water with biochar, a renewable, low cost and sustainable adsorbent–a critical review

    Bioresour. Technol.

    (2014)
  • S. Mondal et al.

    Biosorptive uptake of ibuprofen by chemically modified Parthenium hysterophorus derived biochar: equilibrium, kinetics, thermodynamics and modeling

    Ecol. Eng.

    (2016)
  • V. Nair et al.

    Peroxide-assisted microwave activation of pyrolysis char for adsorption of dyes from wastewater

    Bioresour. Technol.

    (2016)
  • N.S. Nasri et al.

    Assessment of porous carbons derived from sustainable palm solid waste for carbon dioxide capture

    J. Clean. Prod.

    (2014)
  • B. Petrie et al.

    A review on emerging contaminants in wastewaters and the environment: current knowledge, understudied areas and recommendations for future monitoring

    Water Res.

    (2015)
  • R. Pietrzak et al.

    Comparison of the effects of different chemical activation methods on properties of carbonaceous adsorbents obtained from cherry stones

    Chem. Eng. Res. Des.

    (2014)
  • M.G. Plaza et al.

    Production of microporous biochars by single-step oxidation: effect of activation conditions on CO2 capture

    Appl. Energy

    (2014)
  • W.H. Qu et al.

    Converting biowaste corncob residue into high value added porous carbon for supercapacitor electrodes

    Bioresour. Technol.

    (2015)
  • A.U. Rajapaksha et al.

    Enhanced sulfamethazine removal by steam-activated invasive plant-derived biochar

    J. Hazard. Mater.

    (2015)
  • A.U. Rajapaksha et al.

    Engineered/designer biochar for contaminant removal/immobilization from soil and water: potential and implication of biochar modification

    Chemosphere

    (2016)
  • P. Regmi et al.

    Removal of copper and cadmium from aqueous solution using switchgrass biochar produced via hydrothermal carbonization process

    J. Environ. Manage.

    (2012)
  • M.S. Shafeeyan et al.

    A review on surface modification of activated carbon for carbon dioxide adsorption

    J. Anal. Appl. Pyrol.

    (2010)
  • Cited by (0)

    View full text