Removal of Bisphenol A Using Magnetically Responsive Spruce Chip Biochar

Bisphenol A was efficiently adsorbed on biochar magnetically modified with microwave-synthesized magnetic iron oxide particles. The adsorption followed the Langmuir isotherm model, and the maximum adsorption capacity was 77.4 mg per gram of magnetic biochar at 282.15 K. Kinetics of sorption process followed the pseudo-second-order kinetic model, and thermodynamic studies described an exothermic and spontaneous adsorption process. The prepared material exhibited high adsorption of bisphenol A and a rapid magnetic response to an external magnetic field.     

Economic tradeoff between biochar and bio-oil production via pyrolysis

This paper examines some of the economic tradeoffs in the joint production of biochar and bio-oil from cellulosic biomass. The pyrolysis process can be performed at different final temperatures, and with different heating rates. While most carbonization technologies operating at low heating rates (large biomass particles) result in higher yields of charcoal, fast pyrolysis (which processes small biomass particles) is the preferred technology to produce bio-oils. Varying operational and design parameters can change the relative quantity and quality of biochar and bio-oil produced for a given feedstock. These changes in quantity and quality of both products affect the potential revenue from their production and sale. We estimate quadratic production functions for biochar and bio-oil. The results are then used to calculate a product transformation curve that characterizes the yields of bio-oil and biochar that can be produced for a given amount of feedstock, movement along the curve corresponds to changes in temperatures, and it can be used to infer optimal pyrolysis temperature settings for a given ratio of biochar and bio-oil prices.     

A phenomenological model of the mechanisms of lignocellulosic biomass pyrolysis processes

A comprehensive particle scale model for pyrolysis of biomass has been developed by coupling the reaction mechanisms and transport phenomena. The model, which also accounts for the combined effect of various parameters such as particle shrinkage and drying, was validated using available experimental data from the literature. The validated model was then used to study the effect of operating temperature and biomass particle size, both of which strongly influenced the rate of biomass conversion. For example, for particle sizes less than 1 mm, a uniform temperature throughout the particle was predicted, thus leading to higher conversion rates in comparison to those in the larger particles. On the other hand, any increase in moisture content led to considerable decrease in the rate of biomass conversion. For the operating conditions considered in this study, the volumetric particle shrinkage also increased the decomposition of biomass to end products.     

Recent experimental advances on the utilization of biochar as a tar reforming catalyst: A review

Biomass gasification to form syngas is a promising renewable energy production process. Here, biomass is exposed to high temperatures in an oxygen-controlled environment where volatiles react to form components of syngas that can be used for energy or chemical production. A limitation to the use of gasification is the generation of tars that condense in downstream equipment causing damage and halting production. Currently tars are removed by physical, thermal, or catalytic processes, all high-cost options. On the other hand, biochar is produced as a solid by-product of gasification, characterized by high surface area, desirable adsorption properties, and relatively low cost. This review details the use of biochar as a catalyst to reform tars, while highlighting recent experimental advances in evaluating the effects of biomass composition, gasification conditions, and pre-treatment and post-treatment options to improve catalytic function. It discusses tar degradation mechanisms and catalyst deactivation and recommends further areas for research.     

The economic value of biochar in crop production and carbon sequestration

This paper estimates the economic value of biochar application on agricultural cropland for carbon sequestration and its soil amendment properties. In particular, we consider the carbon emissions avoided when biochar is applied to agricultural soil, instead of agricultural lime, the amount of carbon sequestered, and the value of carbon offsets, assuming there is an established carbon trading mechanism for biochar soil application. We use winter wheat production in Eastern Whitman County, Washington as a case study, and consider different carbon offset price scenarios and different prices of biochar to estimate a farm profit. Our findings suggest that it may be profitable to apply biochar as a soil amendment under some conditions if the biochar market price is low enough and/or a carbon offset market exists.     

Nitrogen and oxygen dual-doped porous carbons prepared from pea protein as electrode materials for high performance supercapacitors

Porous carbons as electrode materials are highly desired for use in energy storage/conversion devices. Herein, the development of a series of highly porous nitrogen and oxygen co-doped carbons by using pea protein (PP) as a cost-effective, sustainable and nitrogen-rich precursor is reported. Pea protein derived carbons (PPDCs) have been prepared by applying a straightforward two-step synthetic route including pyrolysis and KOH-chemical activation. Potassium hydroxide has been employed to generate porosity and introduce oxygen functionalities into the framework of carbon. The heteroatoms doping content and porosity parameters have been tuned by varying the synthesis temperature and activator to precursor ratio. The carbon obtained with optimal synthetic parameters (T = 800 °C and KOH/Precursor = 4) featured the highest surface area, the maximal pore volume and N-/O doping level of 3500 m² g^?1, 1.76 cm³ g^?1, and 2.5-/17.9 at%, respectively. PPDC-4-800 as supercapacitor presented a very high specific capacitance (413 F g^?1 at 1.0 A g^?1 in 1 M KOH), remarkable cycling stability (92% retention after 20000 cycles) and outstanding rate capability (210 F g^?1 at 30 A g^?1). The cooperative effects of the well-developed porous architecture and surface modification of PPDCs resulted in enhanced electrochemical performances, suggesting their potential application for energy storage devices.     

Investigation of the carbonization behavior of hybrid poplar

Carbonization experiments of hybrid poplar samples were performed in a thermogravimetric (TG) analyzer to investigate the effect of carbonization conditions, such as heating rate, particle size and sweep gas flow rate on the biochar yield. During carbonization, samples were heated from room temperature to the temperature of 723 K in an inert atmosphere. A statistical design technique was applied by using a two-level factorial design matrix to elucidate the experimental results. It was obtained that the biochar yields of samples were changed depending on the carbonization conditions. Empirical relations between the biochar yield and the carbonization conditions were developed. Biochar yields of samples were decreased with the increasing heating rate and sweep gas flow rate and increased with the increasing particle size. Kinetic analysis of the carbonization TG curves was achieved by using three different methods of calculation; also, 19 different model equations of possible solid-state rate controlling mechanisms were considered. A computer program in BASIC which enables regression analysis was used to calculate kinetic parameters from experimental TG data. It was observed that the carbonization conditions and the method of calculation influenced the kinetic results obtained.