Biochar Applications

Hexavalent chromium (Cr(VI)) contamination has gained interest from regulatory authorities due to its high toxicity and carcinogenicity. Different approaches have been applied for the remediation of Cr(VI) from aquatic media, with adsorption being the most common method. Biochar has gained popularity in recent years as a costeffective and greener adsorbent for remediation of heavy metals (HMs) via different mechanisms, including complexation, electrostatic or ionic interactions, and precipitation. Owing to its facile synthesis methods and excellent physico-chemical properties, biochar has been applied extensively for the removal of Cr(VI) from different matrices. However, very few studies have targeted the elimination of Cr(VI) from real polluted environmental matrices, such as soil or water. Therefore, this review comprehensively discussed the potential application of modified biochar in remediation of Cr(VI) from different environmental matrices, starting with its toxicology impacts on flora and fauna. Furthermore, this review has provided a comprehensive state-of-the-art analysis of biochar tailoring technology, modification methods, various adsorption mechanisms, and factors which influence the adsorption of Cr(VI) from different environmental matrices, along with regeneration and reuse of spent adsorbents. Finally, current work focuses on the major gaps in the literature and areas in which further research should be pursued in addition to the effective application of biochar as adsorbent for the remediation of Cr(VI).

Adsorption is the most widely adopted, effective, and reliable treatment process for the removal of inorganic and organic
contaminants fromwastewater.One of the major issueswith the adsorption-treatment process for the removal of
contaminants from wastewater streams is the recovery and sustainable management of spent adsorbents. This review
focuses on the effectiveness of emerging adsorbents and how the spent adsorbents could be recovered, regenerated,
and further managed through reuse or safe disposal. The critical analysis of both conventional and emerging
adsorbents on organic and inorganic contaminants in wastewater systems are evaluated. The various recovery and regeneration
techniques of spent adsorbents including magnetic separation, filtration, thermal desorption and decomposition,
chemical desorption, supercritical fluid desorption, advanced oxidation process and microbial assisted
adsorbent regeneration are discussed in detail. The current challenges for the recovery and regeneration of adsorbents
and the methodologies used for solving those problems are covered. The spent adsorbents are managed through regeneration
for reuse (such as soil amendment, capacitor, catalyst/catalyst support) or safe disposal involving incineration
and landfilling. Sustainable management of spent adsorbents, including processes involved in the recovery and regeneration
of adsorbents for reuse, is examined in the context of resource recovery and circular economy. Finally, the review
ends with the current drawbacks in the recovery and management of the spent adsorbents and the future
directions for the economic and environmental feasibility of the system for industrial-scale application.

The conversion of food waste and sludge into biogas via anaerobic digestion technology is gaining
attention in recent years, which plays a significant role in waste valorization into bioenergy and promotes
environmental sustainability. Biochar is a carbonaceous material produced via thermochemical
conversion of biomass waste, and tailoring biochar for diverse environmental applications adheres to the
principle of circular economy. The emerging application of biochar as an additive in the anaerobic
digestion of food waste and sludge has been intensively investigated in the last few years. However, a
comprehensive understanding of multifunctional roles of biochar and its mechanisms in the production
of biogas via miscellaneous/complex anaerobic digestion process is yet to be attained. This review
scrutinizes the key roles of biochar as an additive and emphasizes the influences of biochar characteristics
on the anaerobic digestion processes and their capability to address the foremost challenges. This
review also evaluates the techno-economic and environmental impacts of biochar synthesis and its
emerging application for biogas production via anaerobic digestion to make the integrated process more
economical and environmentally sustainable, and identifies challenges and prospects for future studies.

A lot of studies worldwide show that biochar is a powerful tool to address some of the most urgent environmental problems of our time: global warming, soil degradation, water pollution by agro-chemicals, and waste management. In the Philippines, biochar from rice hull is commonly used as soil conditioner and as main ingredient in the production of organic fertilizers.  To popularize the use of biochar in the farm and improve the system of producing it, the Philippine Rice Research Institute (PhilRice) developed the continuous rice hull (CtRH) carbonizer in 2010.  As its name implies, it operates in continuous mode with almost smokeless emission. The heat generated during its operation is recoverable for use as energy source in various farming operations. This action research was conducted in response to the need of a farmer/poultry grower for cost-reducing and environment-friendly technologies for his farm. Specifically, it aims to integrate the CtRH carbonizer in the poultry operations in order to accomplish two things: (a) make use of the carbonizer-generated heat for brooding chicks to replace the conventionally-used liquefied petroleum gas (LPG), and (b) production of biochar as ingredient of organic fertilizer together with the chicken manure. The study involved overcoming challenges of retrofitting the CtRH carbonizer into the automated heating system of a modern tunnel-type poultry house (capacity of 35,000 chickens) that has to comply with the standards set by the broiler integrator whom the farmer was in contract with. Results of the performance test trials showed that the CtRH carbonizer, equipped with heat recovery attachment, can substitute the existing LPG heater to provide the needed heat for brooding chicks, saving 5 to 6 tanks of LPG (50kg/tank) for every one heater replaced. At the price of rice hull and LPG of Php 0.20/kg and Php 70/kg, respectively, a net savings of Php 69,958 per growing period or Php 489,706 per year could be realized per building for brooding. Additional income is expected from the coproduced biochar (1,300kg) which, together with the chicken manure (13,300 kg), can be processed into organic fertilizer.  Moreover, with the integration of the CtRH carbonizer in the poultry operations, greenhouse gas (GHG) emission of around 23 tons CO2e per building per year could be prevented.

This paper aims to examine the influence of biochar produced from lawn waste in accelerating the degradation and mineralization rates of food waste compost. Biochar produced at two different temperatures (350 and 450 °C) was applied at the rates 10 and 15% (w/w) of the total waste to an in-vessel compost bioreactor for evaluating its effects on food waste compost. The quality of compost was assessed against stabilization indices such as moisture contents (MC), electrical conductivity (EC), organic matters (OM) degradation, change in total carbon (TC) and mineral nitrogen contents such as ammonium (NH4+) and nitrate (NO3−). The use of biochar significantly improved the composting process and physiochemical properties of the final compost. Results showed that in comparison to control trial, biochar amended compost mixtures rapidly achieved the thermophilic temperature, increased the OM degradation by 14.4–15.3%, concentration of NH4+ by 37.8–45.6% and NO3− by 50–62%. The most prominent effects in term of achieving rapid thermophilic temperature and a higher concentration of NH4+ and NO3− were observed at 15% (w/w) biochar. According to compost quality standard of United States (US), California, Germany, and Austria, the compost stability as a result of biochar addition was achieved in 50–60 days. Nonetheless, the biochar produced at 450 °C had similar effects as to biochar produced at 350 °C for most of the compost parameters. Therefore, it is recommended to produce biochar at 350 °C to reduce the energy requirements for resource recovery of biomass and should be added at a concentration of 15% (w/w) to the compost bioreactor for achieving a stable compost.

Roselle (Hibiscus sabdariffa L.) plant is a valuable medicinal crop in arid and semi-arid regions. The use of microbes as bio-fertilizers in  enhancing crop production is more favorable than chemical fertilizers due to food safety. A pot experiment was conducted to explore the effect of Azotobacter chroococcum and Azospirillum brasiliense as a bio-fertilizer on the growth, yield, and quietly of roselle plants. Roselle seeds were mixed with the tested biofertilizer and cultivated on plastic pots filled with a sandy clay loam soil. The bio-fertilization significantly (p<0.05) increased the growth, nutrients uptake, yield, and quality of roselle plants compared to the untreated plants. The inoculation of roselle plants with the bio-fertilizer increased the total  chlorophyll, carotenoid, total anthocyanin (TAC), and total flavonel (TF) by 16.45, 26.10, 8.44, and 14.27%, respectively, above the control. The bio-fertilization increased the soil available nitrogen by 14.33% above the control, and increased the uptake of N, P, and K by 18.8, 17.81, and 12.75%. The biofertilization not only increased the quality of roselle plants but also increased the fresh and dry weights of sepals yield by 5.89 and 3.55%, respectively.

Sludge generated from the wastewater treatment plant of a pulp and paper factory was used as feedstock for the preparation of biochar using fast pyrolysis followed by chemical activation with NaOH to make activated biochar (ABC). A process utilising 300 kg/day of waste paper mill sludge (PMS) was designed with a plant utilisation of 80%. A pyrolysis temperature of 500 o C and residence time of 2 h was used in a limited oxygen pyrolysis reactor producing biochar at a yield of 40 %. The biochar was activated using NaOH and heated for an hour at 70 o C to enhance the sorption properties of the ABC. The resulting ABC had a BET surface area of 492.02 m 2 /g, had decolourising properties and a pH of 7, hence applicable in wastewater treatment. A capital investment of US$1 860 729.47 is required and the plant life is 20 years, with a net present value of US$ 1 832 445.94. The rate of return is 29.6 %, return on investment is 26.9% and a payback period of 3.7 years. The production of ABC from PMS is economically feasible, with a product selling price of $30.00/kg.

Utilization of low-cost, abundant and biomaterials is highly recommended for sustainable environment protection. This study presents a comparative analysis on the preparation, characterization and cost analysis of the novel activated biochar (BTS) and activated hydrochar (HTS). Teff (Eragrostis tef) straw was used as a precursor for producing BTS and HTS through pyrolysis and hydrothermal carbonization process, respectively. Both chars were further activated using 30 wt% H 3 PO 4 for 3 h activation time. The physicochemical properties of both chars were compared by different characterization techniques including BET, FTIR, XRD, SEM, and TGA. Briefly, BTS exhibited heterogeneous surface structures and comparatively larger specific surface area (627.7 m 2 /g) than that of HTS (43.8 m 2 /g) with the smooth coalesced carbon layer and dull surface edges. The XRD analysis revealed the amorphous character of HTS which is dominantly composed of AlPO 4 , whilst indicating BTS to be the crystalline structure with the very trivial amount of impurities. The oxygen-containing functional groups increased for HTS in comparison to BTS. Thermogravimetric analysis showed that HTS exhibited better thermal behaviors. Estimated costs incurred in the production of the HTS were found to be cheaper than compared to BTS. Overall, the experiment result suggested that Teff straw could have the potential for producing a low cost activated chars.

Global climatic change leads to many detrimental effects on all life forms. Outstanding case, salinity, and drought are considered multidimensional stress that severely affect plant growth and sustainable agriculture. Thymus vulgaris is a medicinal plant that has phytochemical constituents, and it is threatened by several abiotic stresses caused by climate change. Therefore, the present study aims to evaluate the physiological response and thyme tolerance grown on a newlyreclaimed saline sandy soil under drought conditions and treated by biochar-loaded biofertilizers, nano-zeolite, and nano-silicon through two consecutive seasons. The nanoparticles enhanced plant growth and alleviated the adverse effect of drought. Additionally, a synergistic effect was noticed when combining nanoparticles and biofertilizers. The quadruple combined treatment of nano-zeolite, nano-silicon, biochar, and organic matter (T7) significantly increased thyme morphological traits, photosynthetic parameters, oil, and yield compared to control treatment. Additionally, T7 increased the concentration of endogenous nutrients (N, P, K, Na, Ca, Mg, Zn, Fe, Mn), proline, total phenols, and total flavonoids, in addition to indoleacetic acid, gibberellic acid, and antioxidant enzymes in thyme compared to other treatments. T7 showed the lowest concentration of soluble sugars, abscisic acid, and transpiration rate. Interestingly, T7 increased the medicinal benefits of thyme by increasing its vital hydrocarbons, and oxygenated compounds. These findings introduce a dual benefit of nano-fertilizers in combination with biochar and organic matter in ameliorating soil salinity and drought along with increasing thymegrowth, productivity, and therapeutic value.

An outdoor pot study was conducted to understand what were the effects of different levels of biochar-0%; 4%; 8%; 12%-in variable soil mixes-100% soil; 75% soil and 25% sand; 50% soil and 50% sand-on the growth of potato plants. A two-way ANOVA test was used to analyze the influence of two different independent variables "% of soil/sand" and "% of biochar" on the dependent variable "total plant mass (g)". The results showed that the percentages of biochar had been irrelevant to the yield of the crops. At the same time, two-way ANOVA identified a significant influence given by the different percentages of sand added to the soil. The post-hoc test (Bonferroni) showed the existence of a significant variance (p <0.05) between Soil 1 (100% soil) and soil 2 (75% soil and 25% sand) and soil 1 (100% soil) and soil 3 (50% soil and 50% sand). The results of the experiment show that as the percentage of sand added to the soil increases, the mass of the potato plant decreases. Several factors may have contributed to the insignificance of the addition of biochar on the yield of plants, including the pH levels, the duration of the experiment, and the potential of biochar to sequester nutrients temporarily. However, further analysis would have been necessary to affirm with certainty the real influence of these factors.

Thermochemical conversion of agricultural wastes to bioenergy has a potential to play forefront roles within the context of the food, energy, and water nexus. The biochar solid product of pyrolysis is a promising tool to manage food crop production and water resources by means of soil amendment. The goal of this study was to understand the fate of surface functional groups and higher-atomic-mass elements during the pyrolysis of pecan shell, which is known to accumulate calcium oxalate. Pecan shell feedstock and biochars were analyzed ex situ using X-ray computed microtomography and solid-state 13 C cross-polarization and magic-angle-spinning NMR spectroscopy; the pyrolysis kinetics was monitored in situ by thermogravimetric analysis−gas chromatography (TGA−GC). The NMR spectra indicated the greatest (i) reduction in O/N alkyl functionality and (ii) increase in the aromatic peak between 300 and 500 °C. Primary physical transformation was observed near 400 °C in the tomography slice images and corresponding attenuation coefficients. Key changes in physical structure (microtomography) as well as chemical constituents (solid-state NMR) of pecan shell at 300−500 °C coincided with the evolution of gaseous products (hydrogen, methane, carbon monoxide, carbon dioxide, ethylene, and ethane, as monitored in situ by TGA−GC) occurring at 200−500 °C. These observations followed the reported (i) formation and removal of carboxyl surface functional groups of biochar and (ii) conversion of calcium oxalate to carbonate, both occurring at the key transition temperature near 400 °C. Combined with the mass balance (99.7%) obtained for gas-, liquid-, and solid-phase products, these findings will facilitate reactor design to optimize syngas and bio-oil yields and manipulate the surface reactivity of biochar soil amendment.

Crop residue management becomes the challenging issue to farmers for balancing between the economic and sustainable environment. Though burning is the easiest way of destroying the crop waste it not only causes drastic changes in green house gas but also large amount of nutrients are removed from soil by plants. Hence the technique which protects the environment along with enhancing soil quality is needed. Therefore pyrolysis of crop residue can become an alternate technique against past strategies. The heterogeneous characteristics of the biochar can be produced through the pyrolysis process and that would be employed as a soil amendment. The biochar application ameliorates the problems which persist in soil and enhance the crop production in environmentally sound way. And largely involved in the carbon sequestration thereby sustain the

This study was conducted to investigate the effects of the inoculation of Mesorhizobium ciceri on the nodulation, growth and antagonistic expression against soil-borne fungal pathogens (Phytophthora medicaginis, Fusarium oxysporum and Fusarium solani) on Cicer arietinum L. or commonly known as chickpea grown in vermiculite medium amended with 5% green waste (GW) biochar. The combination of M. ciceri and biochar showed significant effect to chickpea compared with other treatments and control plants in terms of nodulation. The chickpea inoculated with M. ciceri and amended with biochar produced the highest nodule number with an average value of 110 nodules per plant and with an average nodule fresh weight of 57.90 mg per plant at 60 days harvest. The other treatments (M. ciceri only and biochar only) and the positive control (2 mM nitrate-treated plants) produced an average of 55, 65 and 15 nodules per plant with the corresponding average nodule weight of 39.5, 46.5 and 35.6 mg per plant, respectively, 60 days after seed sowing. The combined M. ciceri and biochar also enhanced the shoot length, and fresh and dry weights of chickpea. However, it was observed that the primary root length was shorter than the control but clusters of feeder roots were observed. The combination of M. ciceri and biochar also completely inhibited the colony development of all root pathogenic fungi of chickpea after three days of inoculation. Therefore, the inoculation of M. ciceri in vermiculite medium amended with green waste biochar enhanced the nodulation and growth conditions in chickpea as well as inhibited the growth of root pathogenic fungi P. medicaginis, F. oxysporum and F. solani.

In the context of climate change and the circular economy, biochar has recently found many applications in various sectors as a versatile and recycled material. Here, we review application of biochar-based for carbon sink, covering agronomy, animal farming, anaerobic digestion, composting, environmental remediation, construction, and energy storage. The ultimate storage reservoirs for biochar are soils, civil infrastructure, and landfills. Biochar-based fertilisers, which combine traditional fertilisers with biochar as a nutrient carrier, are promising in agronomy. The use of biochar as a feed additive for animals shows benefits in terms of animal growth, gut microbiota, reduced enteric methane production, egg yield, and endo-toxicant mitigation. Biochar enhances anaerobic digestion operations, primarily for biogas generation and upgrading, performance and sustainability, and the mitigation of inhibitory impurities. In composts, biochar controls the release of greenhouse gases and e...

In the context of climate change and the circular economy, biochar has recently found many applications in various sectors as a versatile and recycled material. Here, we review application of biochar-based for carbon sink, covering agronomy, animal farming, anaerobic digestion, composting, environmental remediation, construction, and energy storage. The ultimate storage reservoirs for biochar are soils, civil infrastructure, and landfills. Biochar-based fertilisers, which combine traditional fertilisers with biochar as a nutrient carrier, are promising in agronomy. The use of biochar as a feed additive for animals shows benefits in terms of animal growth, gut microbiota, reduced enteric methane production, egg yield, and endo-toxicant mitigation. Biochar enhances anaerobic digestion operations, primarily for biogas generation and upgrading, performance and sustainability, and the mitigation of inhibitory impurities. In composts, biochar controls the release of greenhouse gases and e...

In the context of climate change and the circular economy, biochar has recently found many applications in various sectors as a versatile and recycled material. Here, we review application of biochar-based for carbon sink, covering agronomy, animal farming, anaerobic digestion, composting, environmental remediation, construction, and energy storage. The ultimate storage reservoirs for biochar are soils, civil infrastructure, and landfills. Biochar-based fertilisers, which combine traditional fertilisers with biochar as a nutrient carrier, are promising in agronomy. The use of biochar as a feed additive for animals shows benefits in terms of animal growth, gut microbiota, reduced enteric methane production, egg yield, and endo-toxicant mitigation. Biochar enhances anaerobic digestion operations, primarily for biogas generation and upgrading, performance and sustainability, and the mitigation of inhibitory impurities. In composts, biochar controls the release of greenhouse gases and e...

The recent implication of circular economy in Australia spurred the demand for waste material utilization for value-added product generations on a commercial scale. Therefore, this experimental study emphasized on agricultural waste biomass, rice husk (RH) as potential feedstock to produce valuable products. Rice husk biochar (RB) was obtained at temperature: 180 °C, pressure: 70 bar, reaction time: 20 min with water via hydrothermal carbonization (HTC), and the obtained biochar yield was 57.9%. Enhancement of zeta potential value from − 30.1 to − 10.6 mV in RB presented the higher suspension stability, and improvement of surface area and porosity in RB demonstrated the wastewater adsorption capacity. Along with that, an increase of crystallinity in RB, 60.5%, also indicates the enhancement of the catalytic performance of the material significantly more favorable to improve the adsorption efficiency of transitional compounds. In contrast, an increase of the atomic O/C ratio in RB, 0...

Crop residue management becomes the challenging issue to farmers for balancing between the economic and sustainable environment. Though burning is the easiest way of destroying the crop waste it not only causes drastic changes in green house gas but also large amount of nutrients are removed from soil by plants. Hence the technique which protects the environment along with enhancing soil quality is needed. Therefore pyrolysis of crop residue can become an alternate technique against past strategies. The heterogeneous characteristics of the biochar can be produced through the pyrolysis process and that would be employed as a soil amendment. The biochar application ameliorates the problems which persist in soil and enhance the crop production in environmentally sound way. And largely involved in the carbon sequestration thereby sustain the soil quality. However there is lack of information available on effects of long term application of biochar and durability of persistence in soil. ...

Biocomposites are increasingly used in the industry for the replacement of synthetic
materials, thanks to their good mechanical properties, being lightweight, and having low cost.
Unfortunately, in several potential fields of structural application their static strength and fatigue life
are not high enough. For this reason, several chemical treatments on the fibers have been proposed
in literature, although still without fully satisfactory results. To overcome this drawback, in this
study we present a procedure based on the addition of a carbonaceous filler to a green epoxy matrix
reinforced by Agave sisalana fibers. Among all carbon-based materials, biochar was selected for its
environmental friendliness, along with its ability to improve the mechanical properties of polymers.
Different percentages of biochar, 1, 2, and 4 wt %, were finely dispersed into the resin using a mixer
and a sonicator, then a compression molding process coupled with an optimized thermomechanical
cure process was used to produce a short fiber biocomposite with Vf = 35%. Systematic experimental
tests have shown that the presence of biochar, in the amount 2 wt %, has significant effects on the
matrix and fiber interphase, and leads to an increase of up to three orders of magnitude in the fatigue
life, together with an appreciable improvement in static tensile strength.

Biochar is increasingly used as an amendment to improve agricultural soil functions and plant growth. However, the effect of biochar application on plant growth can be different due to high variability in the quality of biochar. In this study the effect of different types of biochar application on the growth of lettuce (Lactuca sativa L.) was assessed in a pot experiment over two period of cultivation in greenhouse. The biochar were produced from four different feedstocks biomass [Vinyard (Vitis vinifera L.), Tomato (Solanum lycopersicum L.), Banana (Musa) and Carnation (Dianthus caryophyllus. L.)] by slow pyrolysis at 300°C and 500°C temperatures and were used to amend the soil. The experiment was design in randomized complete block with five replications and 9 treatments. The treatments included the Control, VB300, TB300, BB300, CB300, VB500, TB500, BB500 and CB500. The trial consisted of a total of 45 pots (4 agricultural waste × 2 pyrolysis temperature × 5 replications) + 5 controls). Two (2) tons da-1 (80 g-1 10 kg-1 pot-1) of biochar was applied with a basic application of fertilizers NPK (18-18-18) and calcium oxide (CaO). The biochar treatments were found to increase plant height and number of leaves in the second cropping cycle in comparison to no biochar treatments. The application of Tomato (TB300) and Banana (BB500) biochar significantly increased plant height by 15.2% and 10.2% respectively. The greatest increase due to biochar additions was found in the soils with tomato biochar treatment and the least increase was found in the soils without biochar application (Control). The second cropping season appeared to be better in terms of yield and quality parameters than the first season. As a result, in this study revealed that a variation in the temperature of pyrolysis does not impact lettuce growth, and recommends a long-term incubation period for further effect of biochar applications on crops.

Because of rapid development in the livestock industry, the production of chicken manure has subsequently increased, which may contribute to environmental pollution. In this regard, in-vessel composting of biochar amended chicken manure and sawdust mixtures was investigated to find out the effect of biochar at the ratios of 0% (control), 3% (T1), 5% (T2), and 10% (T3) on ammonia and greenhouse gases (GHGs) emission, compost quality, pathogenic contaminants and phytotoxicity. The composting process was performed in 100-L, pilot-scale, plastic, cylindrical vessels for 50 days. The addition of biochar (3%, 5%, and 10%) increased the thermophilic temperature with a significant reduction in gaseous emissions (ammonia and CO2), microbial pathogens (Escherichia coli and Salmonella sp.), and phytotoxicity (Lepidium sativum seed germination assay) compared with that of the control compost products. However, according to the obtained results with in-vessel composting, the amendment of 10% biochar showed the most significant effects concerning the quality of the compost nutrients. The study reveals that the addition of biochar during in-vessel chicken manure composting is beneficial in the reduction of gaseous emissions and pathogenic microorganisms apart from improvement in plant nutrients.

Utilization of low-cost, abundant and biomaterials is highly recommended for sustainable environment protection. This study presents a comparative analysis on the preparation, characterization and cost analysis of the novel activated biochar (BTS) and activated hydrochar (HTS). Teff (Eragrostis tef) straw was used as a precursor for producing BTS and HTS through pyrolysis and hydrothermal carbonization process, respectively. Both chars were further activated using 30 wt% H3PO4 for 3 h activation time. The physicochemical properties of both chars were compared by different characterization techniques including BET, FTIR, XRD, SEM, and TGA. Briefly, BTS exhibited heterogeneous surface structures and comparatively larger specific surface area (627.7 m2/g) than that of HTS (43.8 m2/g) with the smooth coalesced carbon layer and dull surface edges. The XRD analysis revealed the amorphous character of HTS which is dominantly composed of AlPO4, whilst indicating BTS to be the crystalline st...

To date, no study has been reported on adsorption capacity (Q e) of palm kernel shell (PKS) biochar for plant nutrients NO 3-, NH 4 + , PO 4 3-and K + (NPK) while most biochar adsorption investigations have not considered the effect of dissolved soil organic matter e.g. humic acid (HA). In our study, we produced PKS biochar at different temperatures and holding times and conducted sorption experiments with a commercial NPK fertiliser and HA. HA-coated PKS biochar was investigated for its capability in adsorbing NPK. Equilibrium adsorption experiments showed that NH 4 + and HA were adsorbed with no effect for NO 3-and PO 4 3-, while K + concentration in solution increased exponentially over time. The highest Q e of NH 4 + (0.522 ± 0.036 mg g-1 ; p&lt;0.05) and that of HA (0.649 ± 0.073 mg g-1) were observed for 400°C PKS biochar. The best-fitted HA sorption with Freundlich isotherm (R 2 = 0.904) reveals a heterogeneous surface and arguably multiple layer sorption of HA. A 55.9% reduc...

Slow pyrolyzed (500±50 °C) ten different waste derived biochar viz. animal bone, corn stover, wood chips, sewage sludge, sugarcane bagasse, green coconut palms, nutshells, potato peels, water hyacinth and organic waste were analyzed to know their physicochemical properties and nutrient contents. Results provided the fact that water hyacinth biochar had the best nutrient status along with excellent physical properties like water holding capacity (509%) and CEC (300 cmolc kg-1) whilst potato peel biochar was the second best among all categories. The average particle size of wood chips biochar 0.82 μm2 was the largest along with the maximum pore depth. However, the region of this biochar occupied by remarkably small particles, which was 47.42%. The corn stover biochar, on the other hand, had the smallest average particle size (0.18 μm2) and the lowest particle area (9.19%). Biochar wood chips (51.3%) and biochar potato peels (49.4%) had the highest organic C value, while biochar nutshell had the lowest (15.31%), respectively. Nutrient content varies depending on the variation in the feedstock mostly N, P, K, and S in total content. Animal bone biochar (3.89%) and biochar nutshells (3.32%) exhibited the highest total N content. Total N biochar content derived from potato peel, water hyacinth, and organic matter had around 3 ppm, which was much higher than the remaining biochar content. In the analysis, high phosphorus concentrations resulted in biochar derived from animal bone feedstock (8.44%), whereas other biochars such as potato peel, water hyacinth, and organic waste were less than 1%. The biochar potato peel and the biochar water hyacinth had higher total K content than other biochars. All the biochars exhibited
equal total S concentration. Biochar derived from animal bone (2.34%) and potato peel (2.72%) had a higher percentage of total K  compared with other biochar. Biochar related wastes showed a very low concentration of heavy metals such as Cr, Pb, Cd, and Ni. The highest chromium content resulted in biochar sewage sludge (0.746 ppm). The concentration of total chromium was similar to that of both sugarcane bagasse biochar and nutshell biochar. The overall amount of lead and cadmium in all of the biochar was below the detection mark. In comparison, the biochar sewage sludge contained a high amount of nickel (1.06 ppm) relative to other biochars. This is perhaps due to the high amount of pollutants present in the sewage sludge feedstock.

Aside from imposing progressively tighter limits to the emissions, the issue of climate change due to increasing atmospheric carbon concentrations can be tackled by very few really practicable and effective countermeasures. Among these, the more viable appears that of removing excess carbon from the air by enhancing large-scale rapidgrowth forestation and then sequestering it in the solid, carbon-rich residue of ad-hoc processes, notably, wood pyro-gasification. The paper, in its first part, presents a novel, simple, robust gasification technology that, when operated in intermittent mode, produces two highly clean products: a solid biochar and a gaseous syngas, without tars and condenses. If the modality is continuous operation (to be discussed in more detail in a companion paper), the syngas production is strongly enhanced, with just a few ashes as residue. The second part of the study addresses two main biochar utilization strategies, one in the agronomic field, highlighting its powerful effect particularly in fostering arboreal seeds' root taking process and the other, in the housing and construction sectors. In these latter cases, the addition of biochar finely ground into lime-based plasters (with and without cement) greatly enhances, as shown in a series of parametric experimental investigations, their performance in terms of thermal insulation and humidity control.