Fabrication of polypropylene/lignin blend sponges via thermally induced phase separation for the removal of oil from contaminated water

Fabrication of Triblock Elastomer Foams and Gelation Studies for Oil Spill Remediation

Polymeric foamed materials are among the most widely utilized technologies for oil spill accidents and releases of oil-contaminated wastewater oil due to their porosity to absorb and separate oil/water effectively. However, a major limitation of traditional polymeric foams is their reliance on an ad/absorption mechanism as the sole method of oil capture, leading to potential oil leakage once their saturation point is exceeded. Tri-block polymer styrene-ethylene-butylene-styrene (SEBS) is a fascinating absorbent material that can bypass this limitation by both capturing oil and providing a sealing mechanism via gelation to prevent oil leakage due to its unique chemical structure. SEBS foams are produced via simultaneous crosslinking and foaming that results in an impressive expansion ratio of up to 15.2 with over 93% porosity. Most importantly, the SEBS foams show great potential as oil absorbents in spill remediation, demonstrating rapid and efficient oil absorption coupled with superhydrophobic properties. Moreover, the unique interaction between the oil and SEBS enables the formation of a physical gel, acting as an effective barrier against oil leakage. These findings indicate the potential for commercializing SEBS foam as a viable option for geotextiles to mitigate oil spill concerns from infrastructures.

Three-Dimensional Printing of Lignocellulose Structures: Improving Mechanical Properties and Shape Fidelity

Additive manufacturing of nanocellulose (NC) materials is an emergent technological domain that facilitates the fabrication of complex and environment-friendly structures that mitigate greenhouse gas emissions. However, printing high concentrations of NC into intricate structures encounters substantial challenges due to inadequate adhesion between the printed layers attributed to a high cellulose solid content, resulting in low shape fidelity and mechanical properties. Therefore, to address these challenges, this paper reports lignin (LG) blending, a nanofiller, in high-content NC (>25 wt % solid content) paste to improve the layer adhesion of three-dimensional (3D) printed structures. The printed structures are dried in a clean room condition followed by postcuring. The optimized lignocellulose (0.5LG-NC) paste showed high structural shape fidelity, remarkable flexural strength, and moduli of 102.93 ± 0.96 MPa and 9.05 ± 0.07 GPa. Furthermore, the volumetric shrinkage behavior in box-like 3D printed structures with optimized LG-NC paste shows low standard deviations, demonstrating the repeatability of the printed structures. The study can be adapted for high-performance engineering and biomedical applications to manufacture high mechanical strength environment-friendly structures.

Porous lignin-based composites for oil/water separation: A review

Frequent oceanic oil spill incidents and the discharge of industrial oily wastewaters have caused serious threats to environments, food chains and human beings. Lignin wastes with many reactive groups exist as the byproducts from bioethanol and pulping processing industries, and they are either discarded as wastes or directly consumed as a fuel. To make full use of lignin wastes and simultaneously deal with oily wastewaters, porous lignin-based composites have been rationally designed and prepared. In this review, recent advances in the preparation of porous lignin-based composites are summarized in terms of aerogels, sponges, foams, papers, and membranes, respectively. Then, the mechanisms and the application of porous lignin-based adsorbents and filtration materials for oil/water separation are discussed. Finally, the challenges and perspectives of porous lignin-based composites are proposed in the field of oil/water separation. The utilization of abundant lignin wastes can replace fossil resources, and meanwhile porous lignin-based composites can be used to efficiently treat with oily wastewaters. The above utilization strategy opens an avenue to the rational design and preparation of lignin wastes with high-added value, and gives a possible solution to use lignin wastes in a sustainable and environmentally friendly way.

In Situ Nanofibrillar Polypropylene-Based Composite Microcellular Foams with Enhanced Mechanical and Flame-Retardant Performances

With the increasing demand for plastic components, the development of lightweight, high strength and functionalized polypropylene (PP) from a cost-effective and environmentally friendly process is critical for resource conservation. In situ fibrillation (INF) and supercritical CO2 (scCO2) foaming technology were combined in this work to fabricate PP foams. Polyethylene terephthalate (PET) and poly(diaryloxyphosphazene)(PDPP) particles were applied to fabricate in situ fibrillated PP/PET/PDPP composite foams with enhanced mechanical properties and favorable flame-retardant performance. The existence of PET nanofibrils with a diameter of 270 nm were uniformly dispersed in PP matrix and served multiple roles by tuning melt viscoelasticity for improving microcellular foaming behavior, enhancing crystallization of PP matrix and contributing to improving the uniformity of PDPP’s dispersion in INF composite. Compared to pure PP foam, PP/PET(F)/PDPP foam exhibited refined cellular structures, thus the cell size of PP/PET(F)/PDPP foam was decreased from 69 to 23 μm, and the cell density increased from 5.4 × 106 to 1.8 × 108 cells/cm3. Furthermore, PP/PET(F)/PDPP foam showed remarkable mechanical properties, including a 975% increase in compressive stress, which was attributed to the physical entangled PET nanofibrils and refined cellular structure. Moreover, the presence of PET nanofibrils also improved the intrinsic flame-retardant nature of PDPP. The synergistical effect of the PET nanofibrillar network and low loading of PDPP additives inhibited the combustion process. These gathered advantages of PP/PET(F)/PDPP foam make it promising for lightweight, strong, and fire-retardant polymeric foams.

Efficient and recyclable sericin-derived carbon aerogel for oils and organic solvents adsorption

Sericin, an industrial waste of the silk industry, is a promising precursor for adsorbent preparation. In this work, an efficient and novel sericin-derived carbon aerogel (SCA) was used to improve the adsorption efficiency of oils and organic solvents. The SCA demonstrated a high-efficiency sorption capacity of not only soybean oil (adsorption capacity reached up to 167.69 times its weight) but also chloroform and methylene chloride (adsorption capacity of 193.67 g/g and 173.25 g/g respectively). It is observed that SCA could be regenerated multiple times through combustion and after five cycles, its adsorbability to ethanol, dimethyl sulfoxide, and soybean oil remained high at 59.08 g/g, 59.34 g/g, and 137.36 g/g, respectively. The physical and chemical characteristics of sericin and SCA were analyzed using Scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), Raman spectra and Fourier transform infrared spectroscopy (FTIR) analysis. The results suggest that SCA is an adsorbent with excellent properties and can significantly increase the adsorption capacity of oils and organic solvents. The overall results indicate that SCA is effectively used as an adsorbent for the adsorption of oils and organic solvents, which will contribute to reduce the discharge of sericin-containing wastewater and alleviate pollution caused by oil and organic solvent leakage.

Using polypropylene needle punch nonwoven sorbents as the interceptor for oil in static and dynamic water experiments

This work was to determine the impact of pore size and thickness of sorbents besides the influence of oil properties on the performance of sorbents used as an interceptor barrier for oils in Static and dynamic water experiments. polypropylene needle punch sorbents were used. SEM test showed the porous structure of sorbents. Oil sorption test investigated that with sorbents had same thickness N1 absorbed oil 8.89 g/g of soybean oil and 7.15 g/g of motor oil. Meanwhile, sorbents with the same pore size, N6 absorbed oil 6.11 g/g of soybean oil and 5.13 g/g of motor oil. All sorbents showed a retention rate of over 75% after 24 h of dripping. Dynamic oil spreading revealed that smaller pore size and higher thickness exhibited higher height wicking. The static performance experiment showed motor oil and soybean oil started to leak at 38 and 32 min for N1, then prolonged with reducing pore size with intercepting efficiency around 70% after 600 min for motor oil and 540 min for soybean oil. In comparison, The motor oil and soybean oil started to leak at 49 and 40 min for N4 and then prolonged with increased thickness with intercepting efficiency around 70% after 480 min for motor oil and 360 min for soybean oil. Under the dynamic experiment, oils spilled quicker with initial leakage of sorbents N3 and N6 at rate flow 55.65 ml/s for motor oil and soybean oil were (41 min, 36 min) and (50 min, 41 min) while intercepting efficiency was (99%, 98.40%) and (99.33%, 98.40%).