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

Evaluating Oil Palm Trunk Biochar and Palm Oil as Environmentally Friendly Sustainable Additives in Green Natural Rubber Composites

This research examines the possibility of palm oil and oil palm trunk biochar (OPTB) from pyrolysis effectively serving as alternative processing oils and fillers, substituting petroleum-based counterparts in natural rubber (NR) composites. Chemical, elemental, surface and morphological analyses were used to characterize both carbon black (CB) and OPTB, by using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) gas porosimetry, and scanning electron microscopy (SEM). The influences of OPTB contents from 0 to 100 parts per hundred rubber (phr) on thermal, dielectric, dynamic mechanical, and cure characteristics, and the key mechanical properties of particulate NR-composites were investigated. OPTB enhanced the characteristics of the composites, as demonstrated by a rise in dielectric constant, thermal stability, storage modulus, glass transition temperature (Tg), hardness and modulus at 300% elongation, along with a decrease in the loss tangent (tan δ). Tear strength exhibited an increase with OPTB content up to a specific threshold, whereas tensile strength and elongation at break declined. This implies a compromise between the various mechanical properties when incorporating OPTB as a filler. This work supports the potential application of OPTB as a renewable substitute for CB in the rubber industry, particularly in tire production and other industrial rubber applications, which would also bring environmental, sustainability, and economic benefits for the palm oil-related industry.

Elucidation of ammonium and nitrate adsorption mechanisms by water hyacinth biochar: effects of pyrolysis temperature

Numerous studies indicate biochar's nitrogen (N) adsorption capacity plays a crucial role in soil N retention. However, there is limited understanding on inorganic N adsorption mechanisms in biochar derived from aquatic weeds such as water hyacinth (WH). This study investigated ammonium-N (NH4+-N) and nitrate-N (NO3--N) adsorption capacities and mechanisms of WH biochar pyrolyzed at different pyrolysis temperatures of 400 °C, 600 °C, and 800 °C (BC400, BC600, and BC800, respectively). Results showed NH4+-N adsorption was maximized (1.07-1.09 mg g-1) with BC400 at initial solution pH 7.0-9.0, while NO3--N adsorption peaked (0.80 mg g-1) with BC800 at initial solution pH 5.0. Both NH4+-N and NO3--N followed well the Pseudo-second-order model in adsorption kinetics (R2 = 0.990-0.997 and 0.962-0.992, respectively). The Sips model accurately described the adsorption isotherms for NH4+-N (R2 = 0.994-0.999) and NO3--N (R2 = 0.992-0.999). The calculated maximum adsorption capacity for NH4+-N and NO3--N using Sips model was 11.2-16.8 mg g-1 and 0.693-4.99 mg g-1, respectively. Co-existing cations and anions reduced NH4+-N and NO3--N adsorption capacity, respectively, with other ions with higher valence exhibiting higher inhibition effects (43%-97% and 44%-73%, respectively). Primary adsorption mechanism for NH4+-N included cation exchange via oxygen-containing surface functional groups in BC400 and pore filling and surface struvite precipitation in BC800. Major adsorption mechanisms for NO3--N included electrostatic interactions in BC400 and pore filling in BC800. These findings suggested that biochar derived from aquatic weeds possessed the same potential usefulness for soil N retention as biochar from other feedstocks, and that it might assist for further detailed considerations in other studies for biochar soil application.

Renewable Carbonaceous Materials from Biomass in Catalytic Processes: A Review

This review paper delves into the diverse ways in which carbonaceous resources, sourced from renewable and sustainable origins, can be used in catalytic processes. Renewable carbonaceous materials that come from biomass-derived and waste feedstocks are key to developing more sustainable processes by replacing traditional carbon-based materials. By examining the potential of these renewable carbonaceous materials, this review aims to shed light on their significance in fostering environmentally conscious and sustainable practices within the realm of catalysis. The more important applications identified are biofuel production, tar removal, chemical production, photocatalytic systems, microbial fuel cell electrodes, and oxidation applications. Regarding biofuel production, biochar-supported catalysts have proved to be able to achieve biodiesel production with yields exceeding 70%. Furthermore, hydrochars and activated carbons derived from diverse biomass sources have demonstrated significant tar removal efficiency. For instance, rice husk char exhibited an increased BET surface area from 2.2 m2/g to 141 m2/g after pyrolysis at 600 °C, showcasing its effectiveness in adsorbing phenol and light aromatic hydrocarbons. Concerning chemical production and the oxidation of alcohols, the influence of biochar quantity and pre-calcination temperature on catalytic performance has been proven, achieving selectivity toward benzaldehyde exceeding 70%.

Succession of biochar addition for soil amendment and contaminants remediation during co-composting: A state of art review

This paper aimed to highlight the succession of biochar addition for soil amendment and contaminants remediation during composting process. Biochar incorporated into the compost mixture promotes composting performance and enhances contaminants reduction. Co-composting with biochar for soil biota has been demonstrated via modified soil biological community abundance and diversity. On the other hand, adverse alterations to soil properties were noted, which had a negative impact on the communication of microbe-to-plant interactions within the rhizosphere. As a result, these changes influenced the competition between soilborne pathogens and beneficial soil microorganisms. Co-composting with biochar promoted the heavy metals (HMs) remediation efficiency in contaminated soils by around 66-95%. Notably, applying biochar during composting could improve nutrient retention and mitigate leaching. The adsorption of nutrients such as nitrogen and phosphorus compounds by biochar can be applied to manage environmental contamination and presents an excellent opportunity to enhance soil quality. Additionally, the various specific functional groups and large specific surface areas of biochar allow for excellent adsorption of persistent pollutants (e.g., pesticides, polychlorinated biphenyls (PCBs)) and emerging organic pollutants, such as microplastic, phthalate acid esters (PAEs) during co-composting. Finally, future perspectives, research gaps, and recommendations for further studies are highlighted, and potential opportunities are discussed.

Carbonized loofah sponge-based solid-phase extraction of benzo[a]pyrene from fish followed by liquid chromatography-ultraviolet detection

A simple and sensitive method combining solid-phase extraction (SPE) and high-performance liquid chromatography-ultraviolet detection (HPLC-UV) was developed for the determination of benzo[a]pyrene (BaP) in fish. Loofah sponge (LS) was carbonized and used as an SPE adsorbent. Carbonization decreased the polarity of LS and enhanced its aromaticity. Carbonized loofah sponge (CLS) could capture BaP better through π-π interaction. The carbonization temperature and the SPE conditions were optimized. The linear range of the developed method was within 10-1000 ng g^-1 with a satisfactory correlation coefficient (R²) of 0.9999. The limit of detection (LOD) was 2.0 ng g^-1, which was below the maximum residue limit (5 μg kg^-1) in meat set by the European Union. The method showed good intra-day and inter-day precision with relative standard deviations (RSDs) ranging from 0.4% to 1.7%. Finally, the developed method was applied to the determination of BaP in fish samples. This method is low-cost and environmentally friendly with natural and renewable LS as raw material and it provides an alternative approach for the efficient and simple determination of BaP in aquatic products.

Efficiency Recycling and Utilization of Phosphate from Wastewater Using LDHs-Modified Biochar

The excessive application of phosphate fertilizers easily causes water eutrophication. Phosphorus recovery by adsorption is regarded as an effective and simple intervention to control water bodies' eutrophication. In this work, a series of new adsorbents, layered double hydroxides (LDHs)-modified biochar (BC) with different molar ratios of Mg2+ and Fe3+, were synthesized based on waste jute stalk and used for recycling phosphate from wastewater. The prepared LDHs-BC4 (the molar ratio of Mg/Fe is 4:1) has significantly high adsorption performance, and the recovery rate of phosphate is about 10 times higher than that of the pristine jute stalk BC. The maximum adsorption capacity of LDHs-BC4 for phosphate was 10.64 mg-P/g. The main mechanism of phosphate adsorption mainly includes electrostatic attraction, ion exchange, ligand exchange, and intragranular diffusion. Moreover, the phosphate-adsorbed LDHs-BC4 could promote mung bean growth, which indicated the recovery phosphate from wastewater could be used as a fertilizer.

Changes in Selected Organic and Inorganic Compounds in the Hydrothermal Carbonization Process Liquid While in Storage

Although many studies have investigated the hydrothermal transformation of feedstock biomass, little is known about the stability of the compounds present in the process liquid after the carbonization process is completed. The physicochemical characteristics of hydrothermal carbonization (HTC) liquid products may change over storage time, diminishing the amount of desired products or producing unwanted contaminants. These changes may restrict the use of HTC liquid products. Here, we investigate the effect of storage temperature (20, 4, and -18 °C) and time (weeks 1-12) on structural and compositional changes of selected organic compounds and physicochemical characteristics of the process liquid from the HTC of digested cow manure. ANOVA showed that the storage time has a significant effect on the concentrations of almost all of the selected organic compounds, except acetic acid. Considerable changes in the composition of the process liquid took place at all studied temperatures, including deep freezing at -18 °C. Prominent is the polymerization of aromatic compounds with the formation of precipitates, which settle over time. This, in turn, influences the inorganic compounds present in the liquid phase by chelating or selectively adsorbing them. The implications of these results on the further processing of the process liquid for various applications are discussed.

Novel synthesis of multicomponent porous nano-hybrid composite, theoretical investigation using DFT and dye adsorption applications: disposing of waste with waste

Extensive studies have shown that doping can enhance the properties of graphene, but the application to real industrial wastewater treatment and theoretical calculations are limited. In this study, the hybrid nanoadsorbent Cu, N co-doped graphene (Cu@NG) was successfully synthesized via green route using carbon rods from waste dry batteries, human urine and copper nitrate, then multiple characterizations, detailed density functional theory (DFT) theoretical calculations and comprehensive actual wastewater tests are performed in environmental applications to investigate the adsorption properties and mechanism. The results showed that Cu@NG surface is mesoporous, decorated with CuO crystals and doped with N atoms. The isotherms and kinetics were simulated by Langmuir and pseudo-second-order models, respectively. The theoretical maximum sorption for MB and CV on Cu@NG is 116.28 mg·g^-1 and CV is 86.96 mg·g^-1, respectively. Pilot tests with Cu@NG on real textile wastewater showed that COD, BOD and color were removed by 54.2%, 55.2% and 86.4%, respectively. The desorption rate of Cu@NG is approximately above 90% for both MB and CV on Cu@NG after six cycles of treatment. The DFT calculations confirmed the experimental results as MB is more reactive than CV molecules. Besides, interactions have been systematically investigated via topology and natural bond orbital (NBO) analyses. The process mechanism involved mainly electrostatic adsorption, π-π stacking interactions and H-bonding interactions and ion exchange.

Feasibility of Biochar Derived from Sewage Sludge to Promote Sustainable Agriculture and Mitigate GHG Emissions-A Review

Sewage sludge (SS) has been connected to a variety of global environmental problems. Assessing the risk of various disposal techniques can be quite useful in recommending appropriate management. The preparation of sewage sludge biochar (SSB) and its impacts on soil characteristics, plant health, nutrient leaching, and greenhouse gas emissions (GHGs) are critically reviewed in this study. Comparing the features of SSB obtained at various pyrolysis temperatures revealed changes in its elemental content. Lower hydrogen/carbon ratios in SSB generated at higher pyrolysis temperatures point to the existence of more aromatic carbon molecules. Additionally, the preparation of SSB has an increased ash content, a lower yield, and a higher surface area as a result of the rise in pyrolysis temperature. The worldwide potential of SS output and CO₂-equivalent emissions in 2050 were predicted as factors of global population and common disposal management in order to create a futuristic strategy and cope with the quantity of abundant global SS. According to estimations, the worldwide SS output and associated CO₂-eq emissions were around 115 million tons dry solid (Mt DS) and 14,139 teragrams (Tg), respectively, in 2020. This quantity will rise to about 138 Mt DS sewage sludge and 16985 Tg CO₂-eq emissions in 2050, a 20% increase. In this regard, developing and populous countries may support economic growth by utilizing low-cost methods for producing biochar and employing it in local agriculture. To completely comprehend the benefits and drawbacks of SSB as a soil supplement, further study on long-term field applications of SSB is required.

Special Issue: "Environmentally Friendly Polymeric Blends from Renewable Sources"

The aim of this Special Issue is to highlight the progress in the manufacturing,characterization, and applications of environmentally friendly polymeric blends from renewable resources [...].

Enhanced ammonium removal on biochar from a new forestry waste by ultrasonic activation: Characteristics, mechanisms and evaluation

The adsorption treatment of ammonium-containing wastewater has attracted significant global attention. Most enhanced adsorption methods employ chemical modification, and there are few reports on physical activation. We present a physical activation to explore whether physical ultrasound may enhance the adsorption performance and comprehensive utilisation of a new forestry waste, Caragana korshinskii was used as a feedstock to prepare activated biochar (ACB) by controlling the pyrolysis temperatures and ultrasound parameters. The optimal parameters were determined via batch adsorption of NH₄⁺, and the adsorption characteristics were assessed by 8 kinds of models and influence experiments. Moreover, the physicochemical properties of ACB during the pyrolysis process were investigated, and the ultrasonic activation and adsorption mechanisms were discussed using multiple characterisation techniques. Additionally, the cost analysis, the safety of the ultrasonic process and disposal method also were evaluated. The results showed that the ultrasonic activation significantly enhanced the NH₄⁺ adsorption efficiency of biochar by approximately 5 times. ACB exhibited the best performance at 500 °C with an ultrasonic activation time of 480 min, frequency of 45 kHz, and power of 700 W. The ultrasonic activation reduced the biochar ash and induced pore formation, which increased the specific surface area through cavitation corrosion and micro-acoustic flow mechanism. The NH₄⁺ adsorption mechanisms comprised physicochemical processes, of which physical adsorption was dominant. The preparation cost of 1 kg ACB was about 0.42 US dollar, and no secondary pollution occurred in the activation process. The findings prove that ultrasonic technology is efficient and convenient for enhancing biochar adsorption performance, and thus is suitable for industrial applications and promotion.

Advanced Biofuels Based on Fischer-Tropsch Synthesis for Applications in Gasoline Engines

The aim of the article is to determine the properties of fuel mixtures of Fischer-Tropsch naphtha fraction with traditional gasoline (petrol) to be able to integrate the production of advanced alternative fuel based on Fischer-Tropsch synthesis into existing fuel markets. The density, octane number, vapor pressure, cloud point, water content, sulphur content, refractive index, ASTM color, heat of combustion, and fuel composition were measured using the gas chromatography method PIONA. It was found that fuel properties of Fischer-Tropsch naphtha fraction is not much comparable to conventional gasoline (petrol) due to the high n-alkane content. This research work recommends the creation of a low-percentage mixture of 3 vol.% of FT naphtha fraction with traditional gasoline to minimize negative effects-similar to the current legislative limit of 5 vol.% of bioethanol in E5 gasoline. FT naphtha fraction as a biocomponent does not contain sulphur or polyaromatic hydrocarbons nor benzene. Waste materials can be processed by FT synthesis. Fischer-Tropsch synthesis can be considered a universal fuel-the naphtha fraction cut can be declared as a biocomponent for gasoline fuel without any further necessary catalytic upgrading.

Advanced Biofuels Based on Fischer-Tropsch Synthesis for Applications in Diesel Engines

This paper focuses on the evaluation of the fuel properties of Fischer-Tropsch diesel blends with conventional diesel. Incorporating this advanced fuel into conventional diesel production will enable the use of waste materials and non-food materials as resources, while contributing to a reduction in dependence on crude oil. To evaluate the suitability of using Fischer-Tropsch diesel, cetane number, cetane index, CFPP, density, flash point, heat of combustion, lubricity, viscosity, distillation curve, and fuel composition ratios using multidimensional GC × GC-TOFMS for different blends were measured. It was found that the fuel properties of the blended fuel are comparable to conventional diesel and even outperform conventional fuel in some parameters. All measurements were performed according to current standards, thus ensuring the repeatability of measurements for other research groups or the private sector.

Preparing Biochars from Cow Hair Waste Produced in a Tannery for Dye Wastewater Treatment

A large amount of cow hair solid waste is produced in leather production, and a reasonable treatment should be developed to reduce the pollution. In this study, cow hair waste was utilized as the carbon precursor, and N₂ was determined to be the most appropriate atmosphere for biochar preparation. We performed a comparison of the properties of biochars that were prepared with different methods, including direct pyrolysis, KOH activation, and the MgO template method. The characterization results show that the highest specific surface area reaches 1753.075 m²/g. Subsequently, the keratin that was extracted from cow hair and purified was used to prepare a biochar with the MgO template method, obtaining an orderly sponge structure. The biochar from cow hair waste was further used to absorb direct blue dye wastewater, and its adsorption capacity reached 1477 mg/g after 10 h with a high efficiency of regeneration. This study successfully utilized keratin-containing hair waste and provides a new source for synthesizing carbon materials for dye wastewater treatment.

Adsorption characteristics and mechanisms of Pb2+ and Cd2+ by a new agricultural waste-Caragana korshinskii biomass derived biochar

In order to explore the comprehensive utilisation and recycling technology of Caragana korshinskii resources, a new agricultural biomass waste, 15 kinds of Caragana korshinskii biochar (CB) were prepared by controlling the pyrolysis temperature and time at the anaerobic environment. Moreover, we pay more attention to deriving the adsorption mechanisms and exploring the difference in adsorption characteristics of Pb²⁺ and Cd²⁺. The optimal preparation conditions and the batch adsorption experiments were evaluated, and the adsorption characteristics and mechanisms were discussed using 8 theoretical adsorption models and multiple characterisation methods. The results showed that the CB prepared at 650 °C for 3 h presented the best performance. The Langmuir and Freundlich models can well simulate the isotherm adsorption process of CB for Pb²⁺ and Cd²⁺, respectively. The adsorption kinetics of CB for Pb²⁺ and Cd²⁺ were best fitted by the pseudo-second-order model. The adsorption equilibrium for Pb²⁺ and Cd²⁺ was reached within 3 h, and their maximum adsorption capacity reached 220.94 mg g^-1 and 42.43 mg g^-1, respectively. In addition, the best addition amount was 3 g L^-1 and 2.2 g L^-1 for Pb²⁺ and Cd²⁺, respectively. The optimum pH range was 3-6 for Pb²⁺ and 6-7.5 for Cd²⁺. The adsorption mechanisms of CB for Pb²⁺ and Cd²⁺ were physicochemical composite adsorption processes, mainly including physical sorption on surface sites, intraparticle diffusion, electrostatic adsorption, ion/ligand exchange, cationic-π interactions, surface complexation and precipitation. Furthermore, the ash of CB also presented a positive effect on the adsorption of Pb²⁺. Compared with other cellulose- and lignin-based biomass materials, CB showed low cost and efficient performance without complicated modification conditions. Therefore, this study demonstrates that CB is a promising raw material in water pollution control to immobilise heavy metals.

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.

Transforming Waste Poly(Ethylene Terephthalate) into Nitrogen Doped Carbon Nanotubes and Its Utility in Oxygen Reduction Reaction and Bisphenol-A Removal from Contaminated Water

Till date, waste plastics are either down-cycled to cheap products like fibers or burnt in incinerators to generate heat. In this manuscript, we report a simple and effective technique for microwave induced transformation of waste polyethylene terephthalate (wPET) to carbon nano-tubes (CNT). Iron nano-particles dispersed on graphene substrate acted as catalyst for CNT growth whereas urea served the dual role of de-polymerisation of wPET and also as nitrogen doping agent. Application of our newly synthesized 3-D meso-porous graphene-nitrogen doped carbon nanotube- iron electrode (Fe@NCNT-rGO) as electro-catalyst for oxygen reduction reaction (ORR) shows a positive half-wave potential (E_1/2) of 0.75 V vs. RHE (reversible hydrogen electrode), nearly ideal four-electron pathway and excellent methanol tolerance when compared to commercial 20% Pt/C. The utility of Fe@NCNT-rGO for removal of bisphenol A from contaminated waters is also reported.