A critical review of the production and advanced utilization of biochar via selective pyrolysis of lignocellulosic biomass
Graphical abstract
Introduction
In the past few years, biomass as an organic solid waste and renewable resource has attracted an increasing amount of attention. Biomass refers to biological materials from living organisms or related biological organisms. Lignocellulosic biomass is composed of carbohydrate polymers (hemicellulose and cellulose) and aromatic polymers (lignin) (Dai et al., 2019a, Dai et al., 2019b), and it can be converted into liquid, gas, and solid products via thermo-chemical conversion (Dai et al., 2019a, Dai et al., 2019b). The resultant solid biochar is a carbonaceous material produced through the thermochemical transformation of biomass in an anaerobic or anoxic environment (Ma et al., 2017a, Ma et al., 2017b). In addition to the main element “carbon”, there are many other elements in biochar that affect the corresponding action and function of materials. Biochar has a porous structure with abundant functional groups (i.e. it is rich in surface free radicals and surface charges) and a high surface area, and also contains minerals and trace metals (Wang & Wang, 2019). Biochar is a reservoir of electron acceptors and donors with a pH buffering capacity and cation exchange capacity (Leng et al., 2020). These properties lend a high reactivity to biochar, and are mainly affected by the composition of the raw materials and production methods (Fig. 1). Production methods include slow or fast pyrolysis (Wang et al., 2016), gasification (Dissanayake et al., 2020), hydrothermal carbonisation (Afolabi et al., 2020), torrefaction (Ma et al., 2019a, Ma et al., 2019b), and flash carbonisation (Kumar et al., 2020a, Kumar et al., 2020b) as well as the regulation of the pyrolysis process and subsequent modification (Leng & Huang, 2018).
Due to its unique physical and chemical characteristics, biochar is often used in the area of removal of water pollutants (Li et al., 2019a, Li et al., 2019b, Li et al., 2019c, Luo et al., 2019), catalysis (Chen et al., 2018a, Chen et al., 2018b, Liu et al., 2018, Wang et al., 2019a, Wang et al., 2019b), composting (Guo et al., 2020), fermentation detoxication (Sun et al., 2020) as well as electrochemical energy storage (Liu et al., 2019a, Liu et al., 2019b, Liu et al., 2019c, Liu et al., 2019d). Biomass raw materials and various process parameters have important influences on the physicochemical properties of biochar, and thus directly determine its use (Ma et al., 2017a, Ma et al., 2017b). The yield, physicochemical properties, and quality of biochar are determined by the composition of biomass raw materials and process conditions under the thermo-chemical conversion platform. The physical and chemical properties of biochar can be improved by its post-treatment (activation and modification) (Yan et al., 2020). In recent years, there has been a great interest in optimising the pyrolysis conditions to improve the yield and quality of biochar; however, there is still a lack of research into the design of biochar and the structure-application relationship between the physicochemical properties and application of biochar.
The purpose of this study was to review and summarize the recent advances on biochar production via selective pyrolysis, biochar design and application. Based on the understanding of the properties of biochar, the development of the preparation system design and application of biochar was reviewed from the perspective of the relationship between physicochemical properties and applications.
Section snippets
Biomass pyrolysis for biochar production
The production process parameters (temperature, residence time, heating rate, and pressure) of biochar have an important impact on its yield, properties (amorphous or porous), and quality (shape, size and chemical composition) (Tripathi et al., 2016). In addition, the composition, structure, and intrinsic binding of the original biomass also influence the physicochemical properties of biochar (Ruan et al., 2019). In recent years, a considerable amount of research has been conducted into the
Pyrolysis regulation for biochar production
As mentioned in Section 2, the properties of biochar are not only closely related to the biomass raw materials, but also to the production conditions, including the temperature, heating rate, and pyrolysis time. However, in addition to altering these pyrolysis parameters, the pyrolysis process of biomass can also be regulated by changing the pyrolysis atmosphere and in-situ activation/doping as a means of obtaining excellent biochar.
Biochar modification
The characteristics of biochar can be further enhanced by activation (physical or chemical) or modification (Wang & Wang, 2019). The latter can be achieved by creating new functional groups on the surface of biochar to prepare biochar matrix composites, or by biological modification (Fig. 1). Some examples of biochar production through methods of activation and modification are provided in Table 3. These methods include the treatment of steam, bases, acids, carbonaceous materials, metal oxides,
Challenge and future research directions
Biochar can be regarded as a renewable and eco-friendly carbon based material. As a new and exciting research field, many gaps and uncertainties still exist in the field of biochar production and valorisation, requiring further investigation.
- (1)
In-depth understanding of biochar structure at multi-scale level. Extensive work is needed to reveal the correlation between the biochar structure features and its properties. The introduction of some free radicals and functional groups and the formation of
Conclusions
As the main pyrolysis product, biochar is influenced greatly by the biomass feedstock and pyrolysis parameters. Biomass with high lignin content contributes the formation of biochar. Among many operation parameters, reaction temperature has a dominant role in the production of high-quality biochar. In addition to improving the quality of biochar by adjusting operating parameters, in-situ activation and doping with heteroatom could alter the properties of biochar obviously, especially the
CRediT authorship contribution statement
Yunchao Li: Writing - original draft. Bo Xing: Formal analysis. Yan Ding: . Xinhong Han: . Shurong Wang: Supervision, Writing - review & editing.
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
The authors acknowledge the financial support from the National Science Fund for Distinguished Young Scholars (51725603), the Project funded by China Postdoctoral Science Foundation (2019M652080), the Innovative Research Groups of the National Natural Science Foundation of China (51621005) and the Open Project of State Key Laboratory of Clean Energy Utilization, Zhejiang University (ZJUCEU2018007).
References (144)
- et al.
Production of biochar from olive mill solid waste for heavy metal removal
Bioresour. Technol.
(2017) - et al.
Valorization of algal waste via pyrolysis in a fixed-bed reactor: production and characterization of bio-oil and bio-char
Bioresour. Technol.
(2017) - et al.
Optimisation and characterisation of hydrochar production from spent coffee grounds by hydrothermal carbonisation
Renew. Energy
(2020) - et al.
Optimized removal of oxytetracycline and cadmium from contaminated waters using chemically-activated and pyrolyzed biochars from forest and wood-processing residues
Bioresour. Technol.
(2017) - et al.
Biochar from extracted marine Chlorella sp. residue for high efficiency adsorption with ultrasonication to remove Cr(VI), Zn(II) and Ni(II)
Bioresour. Technol.
(2019) - et al.
Influence of feedstock on the copper removal capacity of waste-derived biochars
Bioresour. Technol.
(2016) - et al.
Effect of torrefaction on the properties of rice straw high temperature pyrolysis char: pore structure, aromaticity and gasification activity
Bioresour. Technol.
(2017) - et al.
Adsorption of cadmium and lead ions by phosphoric acid-modified biochar generated from chicken feather: selective adsorption and influence of dissolved organic matter
Bioresour. Technol.
(2019) - et al.
Highly efficient adsorption of dyes by biochar derived from pigments-extracted macroalgae pyrolyzed at different temperature
Bioresour. Technol.
(2018) - et al.
Hydrogen production via steam reforming of acetic acid over biochar-supported nickel catalysts
Int. J. Hydrogen Energy
(2018)
Recent developments of post-modification of biochar for electrochemical energy storage
Bioresour. Technol.
Carbon dioxide assisted sustainability enhancement of pyrolysis of waste biomass: a case study with spent coffee ground
Bioresour. Technol.
Production of bio-based phenolic resin and activated carbon from bio-oil and biochar derived from fast pyrolysis of palm kernel shells
Bioresour. Technol.
Activated biochar derived from Opuntia ficus-indica for the efficient adsorption of malachite green dye, Cu+2 and Ni+2 from water
J. Hazard. Mater.
Integrated process of lignocellulosic biomass torrefaction and pyrolysis for upgrading bio-oil production: a state-of-the-art review
Renew. Sustain. Energy Rev.
Post-engineering of biochar via thermal air treatment for highly efficient promotion of uranium(VI) adsorption
Bioresour. Technol.
Initial pyrolysis mechanism of cellulose revealed by in-situ DRIFT analysis and theoretical calculation
Combust. Flame
Sustainable gasification biochar as a high efficiency adsorbent for CO2 capture: a facile method to designer biochar fabrication
Renew. Sustain. Energy Rev.
Thermal conversion of a promising phytoremediation plant (Symphytum officinale L.) into biochar: dynamic of potentially toxic elements and environmental acceptability assessment of the biochar
Bioresour. Technol.
Co-pyrolysis of lignocellulosic and macroalgae biomasses for the production of biochar – a review
Bioresour. Technol.
Dynamic variation in nitrogen removal of constructed wetlands modified by biochar for treating secondary livestock effluent under varying oxygen supplying conditions
J. Environ. Manage.
Evaluation of the adsorption potential of biochars prepared from forest and agri-food wastes for the removal of fluoxetine
Bioresour. Technol.
Removal and biodegradation of naphthenic acids by biochar and attached environmental biofilms in the presence of co-contaminating metals
Bioresour. Technol.
Activated bio-chars derived from rice husk via one-and two-step KOH-catalyzed pyrolysis for phenol adsorption
Sci. Total Environ.
Effects of temperature, oxygen and steam on pore structure characteristics of coconut husk activated carbon powders prepared by one-step rapid pyrolysis activation process
Bioresour. Technol.
Adsorption capacity of phenanthrene and pyrene to engineered carbon-based adsorbents produced from sewage sludge or sewage sludge-biomass mixture in various gaseous conditions
Bioresour. Technol.
The role of biochar in organic waste composting and soil improvement: a review
Waste Manage. (Oxford)
Treatment of furazolidone contaminated water using banana pseudostem biochar engineered with facile synthesized magnetic nanocomposites
Bioresour. Technol.
CO2 gasification of char from raw and torrefied biomass: reactivity, kinetics and mechanism analysis
Bioresour. Technol.
Optimisation of slow-pyrolysis process conditions to maximise char yield and heavy metal adsorption of biochar produced from different feedstocks
Bioresour. Technol.
Removal of methylene blue from aqueous solutions by biochar prepared from the pyrolysis of mixed municipal discarded material
Sci. Total Environ.
An efficient adsorbent: simultaneous activated and magnetic ZnO doped biochar derived from camphor leaves for ciprofloxacin adsorption
Bioresour. Technol.
Ball milled biochar effectively removes sulfamethoxazole and sulfapyridine antibiotics from water and wastewater
Environ. Pollut.
Effect of self-purging pyrolysis on yield of biochar from maize cobs, husks and leaves
Bioresour. Technol.
Characterisation of biochar from maize residues produced in a self-purging pyrolysis reactor
Bioresour. Technol.
Co-production of biochar, bio-oil and syngas from halophyte grass (Achnatherum splendens L.) under three different pyrolysis temperatures
Bioresour. Technol.
Engineered biochar from agricultural waste for removal of tetracycline in water
Bioresour. Technol.
Converting waste lignin into nano-biochar as a renewable substitute of carbon black for reinforcing styrene-butadiene rubber
Waste Manage. (Oxford)
Characteristics of nitrogen and phosphorus adsorption by Mg-loaded biochar from different feedstocks
Bioresour. Technol.
Biochar derived from swine manure digestate and applied on the removals of heavy metals and antibiotics
Bioresour. Technol.
HNO3 modified biochars for uranium (VI) removal from aqueous solution
Bioresour. Technol.
Phosphate adsorption ability of biochar/Mg–Al assembled nanocomposites prepared by aluminum-electrode based electro-assisted modification method with MgCl2 as electrolyte
Bioresour. Technol.
Fabrication of granular activated carbons derived from spent coffee grounds by entrapment in calcium alginate beads for adsorption of acid orange 7 and methylene blue
Bioresour. Technol.
Synthesis of novel magnesium ferrite (MgFe2O4)/biochar magnetic composites and its adsorption behavior for phosphate in aqueous solutions
Bioresour. Technol.
Adsorptive removal of tetracycline from aqueous solution by maple leaf-derived biochar
Bioresour. Technol.
Advances in design strategies for preparation of biochar based catalytic system for production of high value chemicals
Bioresour. Technol.
Analysis of thermal degradation of banana (Musa balbisiana) trunk biomass waste using iso-conversional models
Bioresour. Technol.
Evaluating the effectiveness of various biochars as porous media for biodiesel synthesis via pseudo-catalytic transesterification
Bioresour. Technol.
Biochar potential evaluation of palm oil wastes through slow pyrolysis: thermochemical characterization and pyrolytic kinetic studies
Bioresour. Technol.
An overview of the effect of pyrolysis process parameters on biochar stability
Bioresour. Technol.
Cited by (346)
Lignocellulosic biomass fertilizers: Production, characterization, and agri-applications
2024, Science of the Total Environment