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In this research work, the nano-biochar/thermoplastic polyurethane (TPU) nanocomposite mulching films were successfully prepared by fused deposition modelling (FDM) process. The biochar was prepared by pyrolysis of digitalis purpurea plant at 400 ℃ and the size of biochar was reduced to 80 nm by ball mill method. Various concentrations (0, 2, 4, 6, 8, 10 wt%) of nano-biochar was blended with TPU and the extrusion filament was prepared. The FDM printer was used for the preparation of single-layer mulching films with the thickness of 0.4 mm. The addition of various concentrations of nano-biochar increased the surface colour difference from 14.48 to 63.07 and decreased the light transmittance from 82 to 21%. The hydrophobic properties of nanocomposite mulching films were increased by the incorporation of nano-biochar and the highest value of 116° was achieved for 10 wt% of nano-biochar. The porosity of the films was decreased from 0.7 to 0.2% and the water absorption was increased from 0.1 to 0.43% for 48 h. The tensile and tear strength of the films were increased to 38 MPa and 4.1 MPa. The maximum penetration and impact resistance of 26.7 N and 279 g was achieved for 10 wt% of nano-biochar. The burst strength was increased from 78.2 to 94.5 kPa. The OTR and WVTR was decreased from 1765.45 to 1011.34 cc/m2 day.atm and 19.4 to 11.9 g/m2 day. The lowest frictional coefficient of 0.3 and minimum soil temperature was attained for 10 wt% of nano-biochar. [ABSTRACT FROM AUTHOR]

Purpose: Kaolin has been commonly used to construct the hydraulic barrier of landfill cover. Reduction in desiccation-induced volume shrinkage of compacted kaolin is crucial to reduce the possibility of cracking during desiccation. Nano-biochar has been found to be a potential soil amendment. The present study aimed to investigate the effects of particle size of nano-biochar on the shrinkage behavior of kaolin amended with nano-biochar. Materials and methods: The kaolin used in the present study had an average particle size of 14.5 μm and was classified as high plasticity clay (CH). Two nano-biochars with the same composition but different average particle sizes were adopted, including NB-I of the average particle size of 20 nm and NB-II of 300 nm. Each type of nano-biochar was mixed with kaolin in different mass percentages, including 2%, 4%, 6%, and 10%.The shrinkage properties of pure kaolin and nano-biochar-amended kaolin were determined by wax method. Afterwards, the microstructure and pore-size distribution of the specimens were analyzed by scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP), respectively. Results and discussion: The optimal content of NB-I was 4%, at which the shrinkage limit of kaolin increased by 66.7% (i.e., volume reduction decreased from about 30% to 10%), due to more micropores (pore diameter D < 1000 nm) but less macropores (D > 10,000 nm) after nano-biochar amendment as revealed by MIP test. Yet, the shrinkage limit of the kaolin decreased as NB-I content further increased, when NB-I content exceeded 4%. It was due to more macropores at higher NC-I content (> 4%) caused by the aggregation of the fine nano-particle. In contrast, the shrinkage limit of kaolin increased at a reduced rate as NC-II content increased, which was consistent with the more micropores observed in soil specimens. Conclusions: Nano-biochar was a feasible soil amendment to enhance the shrinkage limit of kaolin and hence reduced the risk of desiccation-induced cracks. From an economic and practical point of view, 4% of NB-I was suggested to reduce volume shrinkage of kaolin and crack formation during desiccation. [ABSTRACT FROM AUTHOR]

Biochar application can reduce losses of runoff from rainfall and increase phosphorus retention on sloping farmland. However, high application rates and high mobility of biochar present a challenge to the ecological environment, emphasizing the need for innovative solutions. This study investigated the potential benefits of applying nano-biochar (NBC) in combination with different crops on sloping farmland. Sloping plots were amended with varying mass contents of NBC (0.1, 0.5, 0.7, 1.0, and 0.0% as the control) by band application and planted with various crops (caragana, alfalfa, soybean, and maize). Simulated rainfall was applied 40–100 min to each plot and the runoff, sediment, and available phosphorus were collected. The results indicated that NBC application could improve rainfall interception on sloping soil by 18.08–31.14% and reduce cumulative runoff and sediment by 10.88–31.75%. With increasing applications of NBC, most of available phosphorus was retained in the soil, and available phosphorus losses were reduced by 22.90–43.01% compared with the control. The 1.0% NBC application and alfalfa combination showed the greatest combined effect in reducing rainwater runoff and phosphorus loss. The combination of crops and NBC application was an effective solution for preventing sediment and phosphorus loss caused by rainfall on sloping farmland. [ABSTRACT FROM AUTHOR]

Phenol, considered as a stable and refractory organic pollutant, has posed an increasing threat to the environment and human health. Herein, the ZnO was regulated with nano-biochar (CCNC) derived from cellulose nanocrystals (CNCs). The CCNC/ZnO photocatalysts were fabricated via in situ precipitation and carbonization, in which CNCs served as both the templates and carbon source. Meanwhile, Zn2+ ions deposited on the surface of rod-like CNCs by electrostatic interaction. Subsequently, homogeneous dispersed ZnO nanoparticles were anchored onto the surface of CNCs, decreasing the ZnO nanoparticles size. As the CNCs transformed into CCNC, the resultant CCNC/ZnO photocatalysts demonstrated excellent degradation efficiency to phenol, corresponding to 99.8% within 90 min. Additionally, the CCNC/ZnO photocatalysts also displayed a satisfactory stability for five cycles without significant performance being decreased. The calculating and experimental results demonstrated that the conjugated graphitic structures of CCNC effectively reduced the band gap of ZnO from 3.26 to 2.96 eV. Besides, the CCNC remarkably promoted photogenerated electron-hole pairs separation and transfer, thereby improving the photodegradation efficiency for phenol. Furthermore, the efficiency for phenol photodegradation was comprehensively influenced by a combination of the ratio of photocatalyst, initial phenol concentration and catalyst dose, and pH value. This study broadened the application of CNCs in the field of photocatalysis, which provided a new perspective for the preparation of highly efficient photocatalysts using CNCs derived nano-biochar as a template and charge-transport pathway. [ABSTRACT FROM AUTHOR]