This research evaluates and compares two microwave pyrolyzed biochars produced from agricultural biomass (shredded hemp stalk) vs woody biomass (maple wood chips) for the removal of Pb (II) from aqueous solution in a batch adsorption study. Biochars were produced by microwave pyrolysis of 1.5 kg of each biomass at an average temperature of 600 ˚C in a stainless steel 309 reactor and then magnetized by mixing aqueous Fe³⁺/Fe²⁺ solutions with aqueous biochar suspensions, followed by treatment with NaOH. The magnetic biochars were characterized and the effects of pH, adsorbent dose, temperature, contact time and initial concentration of Pb (II) solution on their adsorption performance were investigated. The physico-chemical properties of the biochars significantly influence their adsorption capacities. For the cation and system under investigation, the adsorption capacity of magnetic hemp biochar was higher than that of magnetic maple biochar. The higher adsorption efficiency of hemp biochar was correlated to its higher polarity index, pH and zeta potential. Results from kinetics data show that the mechanism for the adsorption of Pb (II) by both adsorbents follows a pseudo-second order (PSO) kinetic model. Isotherm modelling indicates that Freundlich model best described the uptake of Pb (II) by magnetic hemp adsorbent while the loading of Pb (II) onto magnetic maple adsorbent is best characterized by Langmuir model.

Big Box biochar kilns are an alternative to open pile burning that allow for in-woods biochar production in a simple metal box with no moving parts. This approach is based on technology used by charcoal makers for centuries, but with a modern, mechanized approach. A mini-excavator or other piece of machinery is used to operate the kilns. 

The Utah Biomass Resources Group (UBRG) started developing Big Box biochar kilns in 2019 with a Utah Public Lands Initiative Grant. The UBRG has focused on in-woods biochar production and application since 2011. We have focused on simple kiln technology since 2017 with our Oregon kilns which are 1.4 cubic meters in volume. Big Box kilns are 10-20 cubic meters in volume, or about 14 times the volume of Oregon kilns. We partner with the Utah Bureau of Land Management to continually test and improve the kilns and the method of production. Since first being introduced in Utah, Big Box Biochar kilns are being adopted in ten US states, including one at Harvard University, Alberta, Saskatchewan, Ireland and Indonesia.  

One of Big Box biochar kiln is capable of making upwards of 30 cubic meters of biochar in a day, they cost less than $10,000 USD to build, and have no moving parts. Multiple kilns can be run in the same location by a single machine; increasing productivity to more than 100 cubic meters of biochar per day. These kilns have produced biochar in all weather conditions, using a dozen types of woody feedstock, and from pieces as large as one meter in diameter and three meters long, without any feedstock preparation. The biochar we produce from these kilns is in the 85-87% organic carbon range, H:C ratios below .3, and has ash content below 20%. This presentation will outline Big Box biochar kiln best practices including the design, transportation, placement, loading, lighting, quenching, dumping, and safety procedures. 

The oral presentation is based on an investigation carried out between 2017 (a) (b) and 2018 (a). This research was carried out in a plantation of A. mangium located in the village of Planas, department of Meta (Colombia). This research’s objective was to study the effects of biochar obtained through pyrolysis of pruned biomass of Acacia mangium on the chemical properties of soils and the volume of wood in a plantation of Acacia mangium Willd in the Colombian Orinoquía. The purpose was exploring alternatives to mitigate soil degradation has been gaining importance in recent years. Biochar promises to improve properties such as soil fertility and soil conditioning. This research involved an experiment with different levels of biochar in associating it with some chemical properties and the wood yield of A. mangium. To do this, we used a design including nine treatments and three repetitions of each treatment, employing two materials: biochar from Acacia mangium W. (BAM) and synthetic fertilizer (SF). We used a Bayesian principal component analysis to reduce dimensionality, and the two extracted dimensions were labeled by treatment to visualize their grouping. We validated the grouping using cluster analysis algorithms. Volume in wood was used as the response, and the same soil variables were used to run a regression by partial least squares where the explanatory variables were characterized by relative importance.  In terms of results, We found an increase in the different chemical variables of the soil analyzed in treatments with BAM and BAM + SF and an increase in the volume of the stem of the trees in treatments with BAM + SF. The analysis by partial least squares showed how the EC and SOC variables were the most important in explaining the volume of wood. With regard to the conclusions, the responses of the different variables analyzed increased with the addition of biochar, either alone or mixed with synthetic fertilizer. It was also possible to determine that the volume of A. mangium wood was influenced by soil chemical variables. These mixtures, especially those composed of the higher levels, can cause an increase in the response of the set of variables considered. Higher values found in the different variables of chemical properties may be associated with an increase in stem volume and dry weight in A. mangium trees established in plantations in the region.

This study investigates the use of ball milling technology to enhance the adsorption capacity of biochar for methylene blue, a model pollutant. Comparative adsorption studies were conducted on ball-milled biochar and biochar modified chemically through oxidation and alkaline treatment. [1]

Biochar, derived from the pyrolysis of biomass wastes such as wood, crop residues, and municipal waste under limited oxygen conditions at various temperatures, is a low-cost, renewable, and environmentally friendly material. Biochar is increasingly recognized for its high carbon content, cation exchange capacity, large specific surface area, and stability, making it suitable for pollutant removal, for example in wastewater treatment, biochar offers economic and ecological advantages as an adsorbent for dyes, antibiotics, and phenols. [2]

Although chemical and physical modifications (acid/alkali modifications, steam, and plasma) are effective in enhancing the surface area of biochar and adding oxygen-containing functional groups for adsorption of specific pollutants, these methods are not environmentally sustainable because they have high production costs, harsh working conditions, and generate considerable waste. [3]

Alternatively, ball milling presents a green and efficient method to enhance biochar's surface area and adsorption activity. Mechanochemical approach can reduces the grain size of solids to nanoscale particles, transferring kinetic energy to the sample powder through the impact and shear forces of colliding milling balls as well as providing new ionic and covalent functionalizations for different carbon materials. [4-5].Recent studies have shown that ball milling can even increase the oxygen content of carbon materials through exfoliation and fragmentation, though it primarily exposes existing functional groups on biochar surfaces by increasing surface area.

This study compares the adsorption ability of methylene blue on biochar chemically modified by oxidation and alkalization against that of ball-milled biochar. Experiments demonstrated that milling significantly improves biochar’s adsorption capacity without the need for chemical modification and enhances performance by increasing the number of active sites available for adsorption. The reduction in particle size and consequent increase in surface area are hypothesized to be the primary reasons for the enhanced removal efficiency. Adsorption tests were conducted on biochar samples for methylene blue removal at various pH levels (3, 7, 11) and initial concentrations (50-250 mg/L). The mechanically milled biochar consistently exhibited superior performance, achieving an adsorption capacity of 185.18 mg/g and maintaining high efficiency over six reuse cycles.

In summary, the ball milling method significantly enhances biochar's adsorption capacity for methylene blue, without extra chemical modification steps and provides a green and sustainable approach to improving biochar's effectiveness as an adsorbent for water pollutant removal. This mechanically treated biochar shows promise for practical applications in environmental remediation, offering a cost-effective and environmentally friendly alternative to chemically modified biochar and commercial activated carbon.

One of the challenges of promoting accelerated carbonation curing (ACC) of concrete as a carbon sequestration strategy is ensuring that carbonation will not deteriorate mechanical strength. This study examined the mechanical strength, water sorptivity and carbonation efficiency of ten types of mortar containing dry or pre-soaked biochar subjected to internal and/or external carbonation. 

The results obtained enabled a typology of ACC to be proposed, in which the carbon dioxide absorption of mortar containing various types of CO₂-dosed biochar ranged between 0.022% and 0.068% per unit dosage hour. In particular, the mortar containing dry biochar dosed with carbon dioxide was the top candidate for concurrently increasing both compressive strength (54.9 MPa) and carbon dioxide absorption (0.055% per unit dosage hour). 

Mortar containing pre-soaked biochar dosed with carbon dioxide was identified as a strategy that achieved the highest carbonation efficiency (0.068% per unit dosage hour), but it also reduced compressive strength (45.1 MPa). Collectively, the proposed typology offers a useful overview of the different ways by which biochar can be used to tune ACC in mortar, according to any technical constraints and/or intended functions of the carbonated concrete components.

Egypt as an agricultural country produces 30-35 million tons of agricultural residues each year, with only 7 million tons used as animal feed and 4 million as organic manure. Normally, agricultural wastes are simply left in the field to decompose to maintain long-term soil fertility or burn. Although burning is convenient, quick, and cost-effective, and allows fast preparation of the field for the next rotation, it adds a lot of gases to GHG emissions resulting in severe impacts on air quality, biodiversity, and human health. The last issue presents obstacles to human development and threatens natural resources and the environment.

The term carbonization of wastes for biochar processing includes the technologies of pyrolysis, hydrothermal carbonization, flash carbonization, and gasification. Biochar has multifunctional values that include the use for the following purposes: soil amendment to improve soil health, nutrient, and microbial carrier, immobilizing agent for remediation of toxic metals and organic contaminants in soil and water, catalyst for industrial applications, porous material for mitigating greenhouse gas emissions and odorous compounds, and feed supplement to improve animal health and nutrient intake efficiency and, thus, productivity. Biochar contributes to EU circular economy objective significantly and reduces the linear economy of using agricultural and bio-wastes for landfilling and incineration.

However, good quality biochar often requires a complex production process with a robust and effective furnace to make biochar production at high prices. Farmers can’t produce biochar by themselves; thus, it is an obstacle for poor farmers. 

The present research focused on the fact that farmers can deal with their large volumes of crop residues by converting it into biochar using simple  designed reactor manufactured from low cost local materials (used barrels)and  some agricultural resides for heating the feedstock (slow pyrolysis).

The study includes analyses for the different types of biochar produced using different agricultural wastes. Although a significant difference was observed in specific surface area, average pore diameter, pH, CEC, and EC, the study found that different types of biochar produced have suitable properties for soil amendment and carbon sequestration. 

Conclusion:

This category of unit can be suitable for clean, healthy, distributed low-tech biochar production by developing country smallholders and micro-entrepreneurs; “backyard” producers utilizing yard waste; small and urban farmers; nurseries; communal gar

This study was conducted to evaluate the efficacy of biomass and biomass-derived biochar from three different plant source such as Prosopis juliflora, Cocos nucifera (coconut fronds), Acacia moniliformis, and sugarcane bagasse. The calorific value, carbon content, sulfur content, and ash content were analyzed for all the biomass and synthesized biochar specimens. Physicochemical properties of the resulting biochar variants were thoroughly examined and the most suitable biochar was further characterized through high through put techniques FTIR, XRD, and SEM analyses. The findings indicated that biochar produced from Acacia moniliformis displayed superior characteristics in comparison to the other types of biomass investigated. These outcomes indicate the promise of Acacia moniliformis biochar as a viable sustainable energy source and emphasize its relevance in multiple aspects of sustainable energy production and environmental management.