Resource recovery of Eichhornia crassipes as oil superabsorbent

Recent Advances in Biomass-Based Materials for Oil Spill Cleanup

Oil spill on sea surfaces, which mainly produced by the oil leakage accident happened on tankers, offshore platforms, drilling rigs and wells, has bring irreversible damage to marine environments and ecosystems. Among various spill oil handling methods, using sorbents to absorb and recover spill oils is a perspective method because they are cost-effective and enable a high recovery and without secondary pollution to the ecosystem. Currently, sorbents based on biomass materials have aroused extensively attention thanks to their features of inexpensive, abundant, biodegradable, and sustainable. Herein, we comprehensively review the state-of-the-art development of biomass-based sorbents for spill oil cleanup in the recent five years. After briefly introducing the background, the basic theory and material characteristics for the separation of oil from water and the adsorption of oils is also presented. Various modification methods for biomass materials are summarized in section three. Section four discusses the recent progress of biomass as oil sorbents for oil spill cleanup, in which the emphasis is placed on the oil sorption capacity and the separation efficiency. Finally, the challenge and future development directions is outlined.

Biosorption of heavy fuel oil from aqueous solution by Eichhornia crassipes (Mart.) Solms in natura

This work investigated the efficiency of bioremediation of heavy fuel oil (HFO) in aqueous solutions by living Eichhornia crassipes (Mart.) Solms, also known as water hyacinth. Possibility of using post-biosorption macrophytes to produce briquettes was also studied. HFO was characterized by its density, viscosity, and Fourier-transform infrared spectroscopy. Water hyacinth was characterized by scanning electron microscope, pH of zero point of charge, buoyancy, and wettability. Experiments were performed to evaluate effects of contact time and initial oil concentration on biosorption. E. crassipes presented a hydrophobic nature, ideal for the treatment of oily effluents. Hollow structures in macrophytes were also identified, which favor capillary rise and retention of oils of high density and viscosity. Biosorption efficiency of HFO reached 94.8% in tests with initial concentration of 160 mg.L^-1. A calorific value of 4022 kcal.kg^-1 was obtained in briquettes made of water hyacinth post-biosorption. These results reinforce the great potential of E. crassipes as a sustainable and efficient alternative for treatment of oily effluents.

Metal-Organic Framework (MOF) Derived Recyclable, Superhydrophobic Composite of Cotton Fabrics for the Facile Removal of Oil Spills

Marine oil spill cleanup is one of the major challenges in recent years due to its detrimental effect on our ecosystem. Hence, the development of new superhydrophobic oil absorbent materials is in high demand. The third-generation porous materials, namely metal-organic frameworks (MOFs), have drawn great attention due to their fascinating properties. In this work, a superhydrophobic MOF with UiO-66 (SH-UiO-66) topology was synthesized strategically with a new fluorinated dicarboxylate linker to absorb oil selectively from water. The fully characterized superhydrophobic MOF showed extreme water repellency with an advancing water contact angle (WCA) of 160° with a contact angle hysteresis (CAH) of 8°. The newly synthesized porous MOF (S_BET = 873 m² g^-1) material with high WCA found its promising application in oil/water separation. The superhydrophobic SH-UiO-66 MOF was further used for the in-situ coating on naturally abundant cotton fiber to make a superhydrophobic MOF@cotton composite material. The MOF-coated cotton fiber composite (SH-UiO-66@CFs) showed water repellency with a WCA of 163° and a low CAH of 4°. The flexible superhydrophobic SH-UiO-66@CFs showed an oil absorption capacity more than 2500 wt % for both heavy and light oils at room temperature. The superoleophilicity of SH-UiO-66@CFs was further exploited to separate light floating oil as well as sedimentary heavy oil from water. SH-UiO-66@CFs material can also separate oil from the oil/water mixture by gravity-directed active filtration. Hence, the newly developed MOF-based composite material has high potential as an oil absorbent material for marine oil spill cleanup.

Estimation of equilibrium times and maximum capacity of adsorption of heavy metals by E. crassipes (review)

Cellulose emerges as an alternative for the treatment of water contaminated with heavy metals due to its abundant biomass and its proven potential in the adsorption of pollutants. The aquatic plant Eichhornia crassipes is an option as raw material in the contribution of cellulose due to its enormous presence in contaminated wetlands, rivers, and lakes. The efficiency in the removal of heavy metals is due to the cation exchange between the hydroxyl groups and carboxyl groups present in the biomass of E. crassipes with heavy metals. Through different chemical and physical transformations of the biomass of E. crassipesThe objective of this review article is to provide a discussion on the different mechanisms of adsorption of the biomass of E. crassipes to retain heavy metals and dyes. In addition to estimating equilibrium, times through kinetic models of adsorption and maximum capacities of this biomass through equilibrium models with isotherms, in order to design one biofilter for treatment systems on a larger scale represented the effluents of a real industry.

Preliminary study on the electrocatalytic performance of an iron biochar catalyst prepared from iron-enriched plants

Eichhornia crassipes is a hyperaccumulator of metals and has been widely used to remove metal pollutants from water, but disposal of contaminated plants is problematic. Biochar prepared from plants is commonly used to remediate soils and sequester carbon. Here, the catalytic activity of biochar prepared from plants enriched with iron was investigated as a potentially beneficial use of metal-contaminated plants. In a 30-day hydroponic experiment, E. crassipes was exposed to different concentrations of Fe(III) (0, 4, 8, 16, 32 and 64 mg/L), and Fe-biochar (Fe-BC) was prepared by pyrolysis of the plant roots. The biochar was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), Brunauer-Emmett-Teller (BET) analysis, X-ray photoelectron spectroscopy (XPS) and atomic absorption spectrometry (AAS). The original root morphology was visible and iron was present as γ-Fe₂O₃ and Fe₃O₄. The biochar enriched with Fe(III) at 8 mg/L (8-Fe-BC) had the smallest specific surface area (SSA, 13.54 m²/g) and the highest Fe content (27.9 mg/g). Fe-BC catalytic activity was tested in the electrocatalytic reduction of H₂O₂ using cyclic voltammetry (CV). The largest reduction current (1.82 mA/cm²) was displayed by 8-Fe-BC, indicating the highest potential catalytic activity. We report here, for the first time, on the catalytic activity of biochar made from iron-enriched plants and demonstrate the potential for reusing metal-contaminated plants to produce a biochar catalyst.

Estimation of equilibrium times and maximum capacity of adsorption of heavy metals by E. crassipes (review)

Cellulose emerges as an alternative for the treatment of water contaminated with heavy metals due to its abundant biomass and its proven potential in the adsorption of pollutants. The aquatic plant Eichhornia crassipes is an option as raw material in the contribution of cellulose due to its enormous presence in contaminated wetlands, rivers, and lakes. The efficiency in the removal of heavy metals is due to the cation exchange between the hydroxyl groups and carboxyl groups present in the biomass of E. crassipes with heavy metals. Through different chemical and physical transformations of the biomass of E. crassipesThe objective of this review article is to provide a discussion on the different mechanisms of adsorption of the biomass of E. crassipes to retain heavy metals and dyes. In addition to estimating equilibrium, times through kinetic models of adsorption and maximum capacities of this biomass through equilibrium models with isotherms, in order to design one biofilter for treatment systems on a larger scale represented the effluents of a real industry.

Study of the Kinetics and Equilibrium of the Adsorption of Oils onto Hydrophobic Jute Fiber Modified via the Sol-Gel Method

A new kind of hydrophobic and oil sorbent based on jute fiber was successfully prepared by the integration of silica onto a fiber surface via the sol-gel method and subsequent hydrophobic modification with octadecyltrichlorosilane (OTS). Compared with the hydrophilic raw fiber, the modified fiber had a water contact angle (CA) of 136.2°, suggesting that the material has good hydrophobicity. Furthermore, the ability of oil in the oil/water system (taking diesel for example) to absorb was revealed by the kinetics, the isotherm equation, and the thermodynamic parameters. Adsorption behavior was kinetically investigated using pseudo first-order and pseudo second-order models. The data mostly correlated with the pseudo first-order model. The equilibrium adsorption at 298 K was assessed by using the Langmuir and Freundlich isotherm models. The Freundlich model had greater consistency with the experimental data. The obtained thermodynamic parameters demonstrate that the adsorption of diesel is spontaneous, favorable, and exothermic.

Superhydrophobic/superoleophilic cotton-oil absorbent: preparation and its application in oil/water separation

A superhydrophobic and superoleophilic oil sorbent was prepared by attaching SiO₂ particles onto a cotton fiber surface by a sol–gel method and subsequent octadecyltrichlorosilane modification. The surface formation was confirmed by Fourier transform infrared spectroscopy, scanning electron microscopy, and an observation of the water behavior on the cotton surface. The sorption capacity of the modified cotton in pure oil and in an oil/water mixture, the oil adsorption and the reusability were investigated. Compared with raw cotton, the as-prepared cotton absorbed different oils rapidly up to in excess of 25–75 g g⁻¹ its own weight, and the water adsorption was nearly 0 g g⁻¹. The modified cotton fiber could separate oil/water mixtures efficiently through a flowing system. After 10 cycles, the as-prepared cotton was still highly hydrophobic with a 6-times greater adsorption than raw cotton. By a simple modification, a low-cost, high-adsorption and environmentally friendly modified cotton could be prepared that can be considered a promising alternative to organic synthetic fibers to clean up oil spills.

A superhydrophobic and superoleophilic oil sorbent was prepared by attaching SiO₂ particles onto a cotton fiber surface by a sol–gel method and subsequent octadecyltrichlorosilane modification.