Study on the Product Characteristics of Pyrolysis Lignin with Calcium Salt Additives

Adsorption of sulfanilamides using biochar derived from Suaeda salsa: adsorption kinetics, isotherm, thermodynamics, and mechanism

Suaeda biochar (SBC) was prepared by muffle furnace with Suaeda salsa at 600, 700, 800, and 900 ℃. The physical and chemical properties of biochar at different pyrolysis temperatures and the adsorption mechanism of sulfanilamide (SM) were studied by SEM-EDS, BET, FTIR, XRD, and XPS analysis. The adsorption kinetics and adsorption isotherms were fitted. The results showed that the kinetics was in line with the quasi-second-order adsorption model and belonged to chemisorption. The adsorption isotherm conformed to Langmuir adsorption isotherm model and belonged to monolayer adsorption. The adsorption of SM on SBC was spontaneous and exothermic. The adsorption mechanism may be pore filling, hydrogen bonding, and π-π electron donor acceptor (EDA) interaction.

Effects of Ca-Compounds on the Gases Formation Behavior during Molten Salts Thermal Treatment of Bio-Waste

Bio-waste utilization is essential, and pyrolysis is a prominent way for its effective utilization. However, the gradual accumulation of ash compounds in the intermediate products probably affects the thermal conversion characteristics of bio-waste. In the present study, beech wood and disposable chopsticks were selected as bio-waste samples. The effects of typical ash components (Ca-compounds) on volatile formation behavior were investigated during the molten salts thermal treatment of bio-waste. Results demonstrated that about 80% mass of initial bio-waste was gasified into the volatiles at 300 °C. The introduction of Ca-compounds in the molten salts slightly decreased the total yield of gaseous products. More specifically, Ca2+ could improve the generation of CO2 and suppress the generation of other gases (CO, H2, and CH4), and this is accompanied by a reduction in the low heating value (LHV) of the gases. The possible reason is that Ca2+ might act on the -OH bonds, phenyl C-C bond, methoxy bond and carboxylic acid -COOH bonds of the bio-waste to promote CO2 release. In contrast, the introduction of CO32− and OH- tended to relieve the inhibition effect of Ca2+ on the generation of H-containing gases. Meanwhile, the introduction of Ca2+ can promote the conversion of bio-waste into liquid products as well as increase the saturation level of liquid products. Moreover, as a vital form of carbon storage, CO2 was found to be abundant in the pyrolysis gases from molten salts thermal treatment of bio-waste, and the concentration of CO2 was much higher than that of direct-combustion or co-combustion with coal. It’s a promising way for bio-waste energy conversion as well as synchronized CO2 capture by using molten salts thermal treatment, while the introduction of small amounts of Ca-compounds was found to have no significant effect on the change of CO2 concentration.

Lignocellulosic biomass-based pyrolysis: A comprehensive review

The efficacious application of lignocellulosic biomass for the new valuable chemicals generation curbs the excessive dependency on fossil fuels. Among the various techniques available, pyrolysis has garnered much attention for conversion of lignocellulosic biomass (encompasses cellulose, hemicellulose and lignin components) into product of solid, liquid and gases by thermal decomposition in an efficient manner. Pyrolysis conversion mechanism can be outlined as formation of char, depolymerisation, fragmentation and other secondary reactions. This paper gives a deep insight about the pyrolytic behavior of the lignocellulosic components accompanied by its by-products. Also several parameters such as reaction environment, temperature, residence time and heating rate which has a great impact on the pyrolysis process are also elucidated in a detailed manner. In addition the environmental and economical facet of lignocellulosic biomass pyrolysis for commercialization at industrial scale is critically analyzed. This article also illustrates the prevailing challenges and inhibition in implementing lignocellulosic biomass based pyrolysis with possible solution.

Mesoporous Manganese Oxide/Lignin-Derived Carbon for High Performance of Supercapacitor Electrodes

This study explores the modification of lignin with surfactants, which can be used as a template to make mesoporous structures, and can also be used in combination with manganese oxide to produce manganese oxide/lignin-derived carbon. Organosolv extraction, using ethanol (70%) at 150 °C, was carried out to extract lignin from oil palm wood. Lignin was then mixed with Pluronic F-127, with and without Mn(NO₃)₂, and then crosslinked with acidic formaldehyde, resulting in a carbon precursor-based modified lignin. Carbonization was carried out at 900 °C to produce lignin-derived carbon and manganese oxide/lignin-derived carbon. The characterization materials included Fourier transform infrared (FTIR) spectroscopy, scanning electron microscope-energy dispersive X-ray (SEM-EDX) mapping, X-ray diffraction (XRD), and N₂-sorption analysis. FTIR curves displayed the vibration bands of lignin and manganese oxide. SEM images exhibited the different morphological characteristics of carbon from LS120% (lignin with a Pluronic surfactant of 120%) and LS120%Mn20% (lignin with a Pluronic of 120% and Mn oxide of 20%). Carbon LS120% (C-LS120%) showed the highest specific surface area of 1425 m²/g with a mean pore size of 3.14 nm. The largest mean pore size of 5.23 nm with a specific surface area of 922 m²/g was exhibited by carbon LS120%-Mn20% (C-LS120%-Mn20%). C-LS120%Mn20% features two phases of Mn oxide crystals. The highest specific capacitance of 345 F/g was exhibited by C-LS120%-Mn20%.

Xylochemicals and where to find them

This article surveys a range of important platform and high value chemicals that may be considered primary and secondary 'xylochemicals'. A summary of identified xylochemical substances and their natural sources is provided in tabular form. In detail, this review is meant to provide useful assistance for the consideration of potential synthetic strategies using xylochemicals, new methodologies and the development of potentially sustainable, xylochemistry-based processes. It should support the transition from petroleum-based approaches and help to move towards more sustainability within the synthetic community. This feasible paradigm shift is demonstrated with the total synthesis of natural products and active pharmaceutical ingredients as well as the preparation of organic molecules suitable for potential industrial applications.

Utilization of Jujube Biomass to Prepare Biochar by Pyrolysis and Activation: Characterization, Adsorption Characteristics, and Mechanisms for Nitrogen

The rapid advancement of jujube industry has produced a large amount of jujube biomass waste, requiring the development of new methods for utilization of jujube resources. Herein, medium-temperature pyrolysis is employed to produce carbon materials from jujube waste in an oxygen-free environment. Ten types of jujube biochar (JB) are prepared by modifying different pyrolysis parameters, followed by physical activation. The physicochemical properties of JB are systematically characterized, and the adsorption characteristics of JB for NO₃⁻ and NH₄⁺ are evaluated via batch adsorption experiments. Furthermore, the pyrolysis and adsorption mechanisms are discussed. The results indicate that the C content, pH, and specific surface area of JB increase with an increase in the pyrolysis temperature from 300 °C to 700 °C, whereas the O and N contents, yield, zeta potential, and total functional groups of JB decrease gradually. The pyrolysis temperature more significantly effects the biochar properties than pyrolysis time. JB affords the highest adsorption capacity for NO₃⁻ (21.17 mg·g⁻¹) and NH₄⁺ (30.57 mg·g⁻¹) at 600 °C in 2 h. The Langmuir and pseudo-second-order models suitably describe the isothermal and kinetic adsorption processes, respectively. The NO₃⁻ and NH₄⁺ adsorption mechanisms of JB may include surface adsorption, intraparticle diffusion, electrostatic interaction, and ion exchange. In addition, π–π interaction and surface complexation may also be involved in NH₄⁺ adsorption. The pyrolysis mechanism comprises the combination of hemicellulose, cellulose, and lignin decomposition involving three stages. This study is expected to provide a theoretical and practical basis for the efficient utilization of jujube biomass to develop eco-friendly biochar and nitrogenous wastewater pollution prevention.

The Eco-Friendly Biochar and Valuable Bio-Oil from Caragana korshinskii: Pyrolysis Preparation, Characterization, and Adsorption Applications

Carbonization of biomass can prepare carbon materials with excellent properties. In order to explore the comprehensive utilization and recycling of Caragana korshinskii biomass, 15 kinds of Caragana korshinskii biochar (CB) were prepared by controlling the oxygen-limited pyrolysis process. Moreover, we pay attention to the dynamic changes of microstructure of CB and the by-products. The physicochemical properties of CB were characterized by Scanning Electron Microscope (SEM), BET-specific surface area (BET-SSA), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), and Gas chromatography-mass spectrometry (GC-MS). The optimal preparation technology was evaluated by batch adsorption application experiment of NO3-, and the pyrolysis mechanism was explored. The results showed that the pyrolysis temperature is the most important factor in the properties of CB. With the increase of temperature, the content of C, pH, mesoporous structure, BET-SSA of CB increased, the cation exchange capacity (CEC) decreased and then increased, but the yield and the content of O and N decreased. The CEC, pH, and BET-SSA of CB under each pyrolysis process were 16.64-81.4 cmol·kg-1, 6.65-8.99, and 13.52-133.49 m2·g-1, respectively. CB contains abundant functional groups and mesoporous structure. As the pyrolysis temperature and time increases, the bond valence structure of C 1s, Ca 2p, and O 1s is more stable, and the phase structure of CaCO3 is more obvious, where the aromaticity increases, and the polarity decreases. The CB prepared at 650 °C for 3 h presented the best adsorption performance, and the maximum theoretical adsorption capacity for NO3- reached 120.65 mg·g-1. The Langmuir model and pseudo-second-order model can well describe the isothermal and kinetics adsorption process of NO3-, respectively. Compared with other cellulose and lignin-based biomass materials, CB showed efficient adsorption performance of NO3- without complicated modification condition. The by-products contain bio-soil and tail gas, which are potential source of liquid fuel and chemical raw materials. Especially, the bio-oil of CB contains α-d-glucopyranose, which can be used in medical tests and medicines.