Sustainable Use of Leonardite Biopolymers as a Green Alternative in Soil Improvement Methods

Experimental and theoretical evidence for the temperature-determined evolution of PAH functional groups

The diamond nanowire (DNW) film was deposited by N2-enriched microwave plasma-enhanced chemical vapour deposition (MPECVD) process. As-deposited DNW film was treated in O2 plasma which resulted in chemical and microstructural modification. Sheath of the DNW film is chemically constituted by amorphous carbon (a-C)- and graphite (sp2C=C)-like bonding. However, nanowires transformed into ultra-small spherical grains after the O2-plasma treatments. In this condition, a-C and sp2C=C bonding significantly reduced due to plasma etching caused by oxygen atoms. After the O2-plasma treatment, formation of functional groups such as C=O, C–O–C, O–H, O–CH3 and H2O was observed on the surface and inside the wear track as evident from the micro FTIR analysis. H2O is hydrogen bonded to oxygen-containing groups such as –OH and –H. The O2-plasma-exposed DNW film exhibits surface charging and causes formation of dangling bonds and electron trapping centres. This results in significant decrease in contact angle, hence superhydrophilic behaviour. The friction coefficient of O2-plasma-treated film showed super low value ∼0.002 with high wear resistance 2 × 10−12 mm3 N−1 m−1. In the reciprocating ball-on-disc tribology test, only ∼80 nm wear loss was observed after the 1 km of sliding distance at 10 N loads. Such an advance in tribological properties is explained by passivation of covalent carbon bonding and transformation of sliding surfaces by weak van der Waals and hydrogen bondings. High surface energy and the consequent superhydrophilic behaviour of film is attributed to the formation of the above-mentioned functional groups on the surface. This protects against deformation of the wear track leading to extremely high wear resistance.

Nano-ZnO biosynthesis has been carried out using Chaya leaves with the addition of 0.7M NaOH. The aim is to determine the results of nano-ZnO synthesis regarding the formation of functional groups, phase structure, morphology, band gap energy, and its potential as an antibacterial. The synthesis process was carried out in three stages, namely, extraction of Japanese papaya leaves, synthesis of nano-ZnO, and characterization using Fourier Transform Infra Red (FTIR), X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), and UV-Diffuse Reflectance (UV-DRS). Nano-ZnO samples were applied in antibacterial tests. The results of FTIR analysis show the formation of ZnO functional groups at wave numbers 599-509 cm-1 with the main functional groups involved being O-H, C=O, N-H, and C-N. The results of the XRD analysis showed that the phases formed in the sample were zinc oxide, zinc phosphate, zinc iron oxide and zinc chlorate hydrate. Factors that influence the formation of other phases are because Japanese papaya leaves contain phosphorus and iron, the ZnO phase formed has a wurtzite structure. The results of UV-DRS analysis show that the band gap energy is close to the standard of 3.24 eV with an absorbance value of 362 nm. TEM results show that the particle morphology experiences agglomeration due to the presence of other compounds. The antibacterial activity of Nano-ZnO with a NaOH concentration of 0.7 M resulted in an average zone of inhibition of bacterial growth in E.coli of 0.21 mm.

Microbially induced carbonate precipitation (MICP) is a promising biogrouting method for ground improvement. Most studies to date have focused on MICP treatment of uniform clean sands, with few studies having been conducted at large-scale on well-graded soils more representative of in situ deposits. This study presents a laboratory meter-scale MICP test on medium-graded very gravelly sands. The MICP treatment was conducted in a radial flow cell (diameter: ∼1 m; thickness: ∼0.15 m) with an injection well located at the centre and a constant hydraulic head at the outer boundary to replicate field conditions. Aqueous chemistry of the effluent samples inside the flow cell was continuously monitored. Transport modelling and effluent sampling monitoring of the electrical conductivity and pH show that, in general, there was good delivery and reaction of the bacteria and chemicals in the radial flow cell, with some preferential flow paths being present. The MICP-treated soil was subjected to a series of hydraulic and mechanical tests and microstructural analysis. Interestingly, the biocemented medium-graded very gravelly sands had higher strengths (UCS values of 2.6–7.4 MPa) for a given calcite content (9.2–15.1%) than those in comparable studies where uniform soils have been treated. This can be attributed to the higher initial density of grain-to-grain contact points in the medium-graded soil, and a high grain angularity which resulted in particle interlocking and longer grain-to-grain contact surfaces, as can be seen from Scanning Electron Microscopy images. Consolidated-drained triaxial tests on two cores showed peak deviatoric strengths of 5.9 MPa and 3.7 MPa under an effective confining stress of 100 kPa, with the clear formation of shear bands during shearing, compared to a peak deviatoric strength of 0.5 MPa determined for the untreated soil. MICP treatment clearly enhanced the shear strength and stiffness of the material. The study shows that formation of preferential flow paths may be a challenge for producing uniform biocementation in field applications of MICP. We propose that successful MICP treatment in heterogeneous soils will require a well-designed and well-executed site investigation programme that can identify, a priori, the geometry of any significant high or low permeability features within the soil body to inform the final MICP treatment strategy.

Ulva species is consumed macroalgae, and it has rich polysaccharides. Nanoparticles play an important role in medicine, agriculture, and environment. Extracts from bacteria, algae, and plants can be used for synthesis of nanoparticles fields. The study determines the biogenic synthesis and characterization of iron oxide nanoparticles by U. rigida extract. The size, nature, stability, and composition of green synthesized iron oxide nanoparticles were characterized using UV-Vis, XRD, FTIR, FESEM, EDX, and TGA analysis. UV-Vis and FTIR analysis were performed to determine the surface plasmon resonance and occurrence of functional groups in the U. rigida-mediated iron oxide nanoparticles. FTIR spectra proved the formation of metal oxide functional groups. U. rigida-mediated iron oxide nanoparticles were spherical in shape with the average size of 50-60 nm and confirmed by FESEM analysis. Crystalline nature of U. rigida-mediated iron oxide nanoparticles was synthesized. A weight loss of 30.1% U. rigida-mediated iron oxide nanoparticles was observed in TGA analysis and confirms its high thermal stability. The study reveals that U. rigida extract can be used for stabilizing agents for fabrication of iron oxide nanoparticles. The synthesized iron oxide nanoparticles may be used in wastewater treatment and drug delivery system.

Physico-chemical aspects of polyethylene processing in an open mixer 4. Comparison of PE-LLD and PE-HD with PE-LD

Coupling effect of pond ash and polypropylene fiber on strength and durability of expansive soil subgrades: An integrated experimental and machine learning approach

In order to explore the influence mechanism of carbon nanotubes on the ultraviolet (UV) aging properties of the SBS-modified asphalt binder, the changes of functional groups in the one-dimensional infrared spectrum and two-dimensional infrared correlation spectrum are studied in this paper. The results show that the UV aging process of the SBS-modified asphalt binder is the process of alkane chain cleavage and reorganization, the formation of oxygen-containing functional groups and decomposition of SBS. The incorporation of carbon nanotubes can reduce the mutual conversion of methyl and methylene functional groups, inhibit the decomposition of butadiene and the destruction of C = C double bonds in SBS. The degradation of SBS during the process of UV aging leads to the change of many functional groups and acceleration of the aging of the SBS-modified asphalt binder. The addition of carbon nanotubes can effectively alleviate the degradation of SBS and the formation of oxygen-containing functional groups at the early stage of UV aging, and reduce the influence of these two changes on other functional groups; thus, improving the anti-aging performance of the SBS-modified asphalt binder.

Pore development and the formation of oxygen functional groups were studied for activated carbon prepared from bamboo (Bambusa bambos) using a two-step activation with CO2, as functions of carbonization temperature and activation conditions (time and temperature). Results show that activated carbon produced from bamboo contains mostly micropores in the pore size range of 0.65 to 1.4 nm. All porous properties of activated carbons increased with the increase in the activation temperature over the range from 850 to 950 °C, but decreased in the temperature range of 950 to 1000 °C, due principally to the merging of neighboring pores. The increase in the activation time also increased the porous properties linearly from 60 to 90 min, which then dropped from 90 to 120 min. It was found that the carbonization temperature played an important role in determining the number and distribution of active sites for CO2 gasification during the activation process. Empirical equations were proposed to conveniently predict all important porous properties of the prepared activated carbons in terms of carbonization temperature and activation conditions. Oxygen functional groups formed during the carbonization and activation steps of activated carbon synthesis and their contents were dependent on the preparation conditions employed. Using Boehm’s titration technique, only phenolic and carboxylic groups were detected for the acid functional groups in both the chars and activated carbons in varying amounts. Empirical correlations were also developed to estimate the total contents of the acid and basic groups in activated carbons in terms of the carbonization temperature, activation time and temperature.

Numerical study of the effects of surface nitrogen-containing on soot formation process in ammonia/ethylene counterflow diffusion flames

The presence of dyes in wastewaters from the textile industry, even in concentrations of less than 1 mg/l, significantlyaffects the aesthetic properties and transparence degree of public effluents, with direct repercussions on theenvironment. Cerioporus squamosus White-Rot-Fungi (WRF) strain was used for bio-augmentation of MBBR carriers(consisting of a mix of 88% High Density Polyethylene, 5% talcum and 7% cellulose). Cerioporus squamosus, also oftenencountered as Polyporus squamosus, is a basidiomycete bracket fungus, able to cause “white rot” on decaying wood.The bio-functionalized carriers were used for treatment of a synthetic wastewater sample, of Bemacid ROT (Bezema)azo-dye. Azoic dyes represent one of the most important classes of synthetic dyes used in the textile industry,accounting for over 60–70% of the dyes used in this industry. In the case of reactive groups of azo dyes (-N=N-), dueto the low degrees of fixation on the fiber, there are losses of dyes in solution of up to 50%. Infrared spectral (FT-IR)analysis was carried out for determination of functional groups involved in biodegradative processes. Thus, the obtainedIR spectra, different from those of initial Bemacid ROT dye, the disappearance or decrease of the signal specific to azoicbonds from the initial sample, the formation of new functional groups, the disappearance of intermolecular hydrogenbonds simultaneously with increase of transmittance values for amino groups, resulted in highlighting the degradationof Bemacid ROT dye by the bio-augmented HDPE carriers.

The presence of dyes in wastewaters from the textile industry, even in concentrations of less than 1 mg/l, significantlyaffects the aesthetic properties and transparence degree of public effluents, with direct repercussions on theenvironment. Cerioporus squamosus White-Rot-Fungi (WRF) strain was used for bio-augmentation of MBBR carriers(consisting of a mix of 88% High Density Polyethylene, 5% talcum and 7% cellulose). Cerioporus squamosus, also oftenencountered as Polyporus squamosus, is a basidiomycete bracket fungus, able to cause “white rot” on decaying wood.The bio-functionalized carriers were used for treatment of a synthetic wastewater sample, of Bemacid ROT (Bezema)azo-dye. Azoic dyes represent one of the most important classes of synthetic dyes used in the textile industry,accounting for over 60–70% of the dyes used in this industry. In the case of reactive groups of azo dyes (-N=N-), dueto the low degrees of fixation on the fiber, there are losses of dyes in solution of up to 50%. Infrared spectral (FT-IR)analysis was carried out for determination of functional groups involved in biodegradative processes. Thus, the obtainedIR spectra, different from those of initial Bemacid ROT dye, the disappearance or decrease of the signal specific to azoicbonds from the initial sample, the formation of new functional groups, the disappearance of intermolecular hydrogenbonds simultaneously with increase of transmittance values for amino groups, resulted in highlighting the degradationof Bemacid ROT dye by the bio-augmented HDPE carriers.

Transformer is crucial equipment in the transmission of electric power. Various types of insulating materials used in the transformer among those mineral oil or transformer oil is used for the insulation. To reduce the failure percentage of transformer it is necessary to maintain the purity of oil. This paper investigates work on different properties of aged transformer oils and pure transformer oil. The aged oils are taken as filtered and unfiltered after using in the transformer. The electrical, physical and chemical properties are investigated for pure and aged transformer oils. UV-spectroscopy is used to test the quality of oil based on the absorbance value and FTIR analysis is performed to determine the functional groups existing in the pure and aged transformer oils. The results showed that breakdown strength is less for used transformer oil due to formation of acidic functional groups. The absorption peak is high for unfiltered oil followed by filtered oil and pure oil.

Linear low-density polyethylene (LLDPE) waste presents a major environmental concern due to its high and widespread use. This study explores the potential of fungal mycelium as a bioremediation solution for LLDPE degradation, by evaluating on mycelial growth efficiency, ligninolytic enzyme activity, weight loss, surface morphology changes, and economic feasibility. Among the tested fungal species, Schizophyllum commune WE032, Lentinus sajor-caju TBRC6266, and Trametes flavida AM011, S. commune demonstrated the most vigorous mycelial expansion (20.53 mm/day) and highest biomass accumulation (276.87 mg). Screening for ligninolytic enzymes revealed significant laccase (Lac) and manganese peroxidase (MnP) activity in all three species indicating their potential in polymer degradation. Weight loss analysis showed that S. commune achieved the greatest LLDPE degradation (1.182% after 30 days), highlighting its enzymatic and metabolic efficiency in breaking down synthetic polymers. Surface morphology studies supported these findings, revealing substantial erosion was observed in LLDPE sheets treated with S. commune and L. sajor-caju, confirming their effectiveness in polymer disruption. FTIR analysis indicated the formation of new functional groups and alterations in the carbon backbone, suggesting active depolymerization processes. Economic evaluation demonstrated that fungal biodegradation is a cost-effective and environmentally sustainable strategy, aligning with circular economy principles by enabling the generation of value-added products from plastic waste. Additionally, fungal-based waste treatment aligns with circular economy principles, generating value-added products while mitigating plastic pollution. These findings highlight fungal mycelium's potential for plastic waste management, advocating for further research on optimizing growth conditions, enhancing enzyme expression, and scaling industrial applications. Future research will focus on integrating fungal bioremediation with biomass residues from agricultural and forestry sectors, offering a comprehensive solution for waste management and environmental sustainability.

Impact of gamma irradiation on structural, thermal, and rheological properties of talipot palm (Corypha umbraculifera L.) starch: a stem starch