Synthetic Sorbents Research Articles

Activation of bentonite and palygorskite adsorbents by acid under microwave radiation

The problem of wastewater treatment, since the second half of the 20th century, is relevant for all countries of the world. There are quite a few purification methods, however, adsorption methods are simple and effective methods of water purification. The advantages of these methods are high efficiency, the possibility of treating wastewater containing several substances, as well as the recovery of these substances. Active carbons, synthetic sorbents and some production wastes (ash, slag, flask, sawdust), mineral sorbents - clays, silica gels, alumogels and metal hydroxides are used as sorbents. The research illustrates the possibility of acid activation of bentonite and palygorskite clays using microwave radiation. It has been established that the microwave activation of bentonite leads to the destruction of the structure, the expansion of the surface and the change in the pore structure, which affects the textural characteristics. The concentration values of hydroxyl groups indicate the presence of surface active sites that can participate in adsorption. The results were presented as tables and as a graph.

A sustainable approach to oil spill cleanup by kapok and waste cotton needle punched nonwoven blends

Natural materials that can absorb a large amount of oil have recently received a lot of interest as sorbents to clean up oil spills in seawater. In this work, kapok fibre was blended with different proportions of cotton fibres obtained as blow room waste from the textile industry to prepare nonwovens using carding and needle-punching techniques. The potential for oil sorption, oil retention, and water sorption of kapok/waste cotton nonwovens was investigated. FTIR, SEM, and surface contact angle of the fibres were determined since oil sorption depends on the fibres' physical and chemical properties. The effect of waste cotton and kapok fibre blend ratio on oil sorption and oil retention behaviour of kapok/cotton nonwoven was studied. The maximum oil sorption capacity of blended nonwoven (90/10, kapok/cotton) with areal density (150 GSM or g/m 2 ) was 45.36 g/g, 43.97 g/g, and 39.92 g/g for engine oil, vegetable oil, and diesel oil, respectively. Reusability test results suggest that after ten cycles, the oil absorbency of 150K/C 90/10 was 42.55 g/g, 40.61 g/g, and 36.45 g/g against engine oil, vegetable oil, and diesel oil, respectively. A comparison of the oil sorption capacity of kapok/waste cotton blends with other synthetic (Polypropylene) sorbents was also presented. According to our findings, kapok/waste cotton nonwovens could become an important sorbent for oil spill clean-up. • Sustainable oil sorbent was made from blends of kapok and waste cotton fibres. • The oil-to-pore volume occupied by fibre was explored for oil sorption capacity. • After ten cycles, K/C blend sorbents retained 76 % of engine oil. • The sorbents can be used as biofuel even after 10th cycle.

ПЕРСПЕКТИВНЫЕ СОРБЕНТЫ ДЛЯ ИЗВЛЕЧЕНИЯ НИКЕЛЯ И КОБАЛЬТА В ГИДРОМЕТАЛЛУРГИЧЕСКОЙ ПЕРЕРАБОТКЕ НИКЕЛЕВЫХ РУД

The paper provides a critical analysis of the sources, a generalization of the factual and theoretical material on the properties, the use of natural and synthetic sorbents for the extraction of nickel and cobalt from productive solutions after the leaching of nickel ores. Comparison of promising sorbents in terms of efficiency of their use with sorbents used in industry has been carried out. Sorption processes using natural substances or synthetic resins contribute to the selective extraction of nickel and cobalt from aqueous solutions. Zeolites modified with various functional groups are very promising materials for selective recovery. The ability to selectively extract metal cations and the possibility of regeneration makes ion-exchange polymer resins one of the leading sorbents in the modern world. The polymer resin sorption process avoids wastage of reagents, costly filtration, and poor selectivity for nickel and cobalt over other metal ions associated with solvent extraction processes. A comparison of the values of the sorption capacities of natural sorbents shows the promise of using silicate minerals - montmorillonite and palygorskite in industry, as well as the development of technological processes using them. Analysis of the recovery rates of synthetic polymer resins proves the frequent use of Amberlite, Dowex and Ionac in the industry. However, Dowex M4195 has the highest nickel selectivity due to the presence of a bis-picolylamine functional group, unlike other resins with an iminodiacetate group. In addition, the disadvantage of foreign-made chelate resins is their high cost, which cannot be said about the cation exchanger grade KU 2-8 of a Russian manufacturer.

Effect of sulfur dioxide on adsorption capacity of zeolite sorbents for carbon dioxide

The article discusses a rather serious problem limit-ing the use of adsorption for the CO2 capture from flue gas, in the presence of sulfur dioxide. An apparatus with a vertical batch adsorber was constructed to study adsorption under elevated pressure in a wide range of temperatures and evaluation of CO2 breakthrough curves with an infrared analyzer. The article summarizes the results of experiments conducted with zeolite clinoptilolite, which represented natural materials, and molecular sieve 13X as a representative of synthetic sorbents. Adsorption capacities achieved during cyclically repeated tests with a model gaseous mixture free of SO2 and a mixture of the same composition but enriched with a low volume fraction of SO2 (0.3 %) were compared. Adsorption took place at a temperature of 20 °C and at two overpressures (200 and 500 kPa) of the gas with a 13 % volume fraction of CO2. Each sub-experiment consisted of five adsorption and desorption cycles, where desorption was based on depressurization followed by temperature increase to 120 °C under nitrogen atmosphere. There were no changes in capacities when tested with the gaseous mixture without SO2. Relative to the weight of the sample, the 13X sample at an overpressure of 500 kPa had a capacity of 11.3 % and clinoptilolite 3.8 %. Tests in the presence of SO2 led to a permanent reduction of the equilibrium capacities for both samples and at both pressures. At the overpressure of 500 kPa, the capacity decreased to 7.4 % for the 13X and to 2.5 % for the clinoptilolite. A more intensive desorption involving a thermal and vacuum step did not lead to any improvement for the 13X sample. In contrast, the effect for clinoptilolite was very positive. Its capacity in the fifth cycle reached 3.4 % close to the state without SO2 exposition. In the case when SO2 in the gas was accompanied with 40 % relative humidity, vacuum desorption did not lead to positive results in any case. After five cycles, the capacity of 13X dropped to 3.2 % and clinoptilolite to 1.4 %. When moisture, SO2 and the presence of O2 (volume fraction of 6 %) in the model mixture were further combined, the capacity of 13X decreased to 1.4 % and clinoptilolite to 0.4 % after five cycles. Tests with SO2 (dry gas) caused a decrease in the specific surface area from 512 to 211 m2.g‒1 for the 13X sample. On the other hand, for clinoptilolite it decreased from only 29 to 28 m2.g‒1 under the same conditions. Ac-cording to XRF, it was not possible to remove sorbed SO2 from the 13X sample even by evacuation followed by heating up to 200 °C. Using the XRD method, it was found that SO2 remains in the matrix, although it does not undergo transition to the crystalline phase. The study verified that synthetic molecular sieve 13X, unlike natural clinoptilolite, is not applicable for CO2 adsorption from SO2 containing flue gas.

Твердофазные сорбенты на основе синтетических нановолокон и глауконита для извлечения магнезона I из водных сред

A comparative evaluation of the sorption capacity of synthetic and natural sorbents with respect to phenol and some of its derivatives has been carried out. Electrospun nanofibers based on polyamide-6 (PA-6) were obtained under optimal conditions from a spinning solution of a polymer dissolved in a mixture of formic and acetic acids. The preparation of the clay mineral by the sieve method has been carried out, while the enriched fraction of glauconite (200–500 microns) has been isolated. The morphology of unmodified nanofibers, as well as glauconite, has been studied by scanning electron microscopy. Preliminary experiments showed low efficiency of sorption of phenol and some of its nitro- and chlorine derivatives by the sorbents used in this work. To improve the sorption characteristics, the method of derivatization of initialanalytes by diazotization and azo coupling reactions has been used. The concentrations of magneson I (nitrophenylazo-derivative of resorcinol) have been determined spectrophotometrically using a calibration dependence in the range of magneson I molar concentrations from 3·10-6 to 2·10-5 mol/l. The sorption capacity of glauconite from the Saratov region (Beloozerskoye deposit) and synthetic nanofibers based on PA-6 with respect to magneson I has been studied. The effect of pH on the sorption efficiency of magnezone I by glauconite and nanofibers based on PA-6 has been evaluated, in addition, the extraction coefficients of magnezone I by these sorbents have been calculated, which were in the range of 88–100% at optimal pH (≈3–6). The experiments performed on a model compound, magnesone I, led to the conclusion about the potential possibility of using glauconite from the Beloozerskoye deposit in the Saratov region and nanofibers based on polyamide-6 for the extraction of phenols in the form of their azo derivatives from various waters.

Facile, time-saving cigarette butt-assisted combustion synthesis of modified CaO-based sorbents for high-temperature CO2 capture

Highly efficient and stable Zr-incorporated CaO-based sorbents were synthesized using a facile, cigarette butt-assisted combustion synthesis (CAC) method. Comparative investigation of CAC method with two common synthesis methods (i.e., wet-mixing, sol–gel) on producing CaO-based sorbents was conducted. The sorbents synthesized by the CAC and sol–gel methods exhibit superior cyclic CO2 capture capability compared to wet-mixing. More importantly, the CAC belongs to impregnated layer solution combustion synthesis and takes markedly shorter time compared to sol–gel, possessing the potential of scaled-up preparation. The optimization of combustion temperature and incorporation ratio of Zr-based support on synthesis of CaO-based sorbents by CAC method was further conducted. The proper combustion temperature selected to synthesize Zr-incorporated CaO-based sorbents using CAC method is 750 °C. Too high or low combustion temperature may result in unsatisfactory pore structure of synthetic CaO-based sorbents because of excessive sintering or generating in-situ CaCO3, respectively. The synthetic CaO-based sorbents with 25 wt% of ZrO2 exhibit the outstanding CO2 capture performance (CaO carbonation conversion of 63.8% after 17 cycles) due to the generation of extensive CaZrO3 grains acting as the inert skeleton. Additionally, the combination of cigarette butt-assisted combustion and graphite-moulding can prepare Zr-incorporated CaO-based pellets with desirable practicality.

Elimination of Terbinafine Hydrochloride Antifungal Drug Traces from Water, Pharmaceutical Formulations and Blood Plasma using Low-Cost Bio and Synthetic Sorbents

<p>:<strong> </strong>Chitosan (CS) biosorbent and polyurethane foam (PUF) synthetic sorbent have been utilized to eliminate terbinafine hydrochloride (TRB HCl) antifungal drug in its pure and pharmaceutical forms from both contaminated aqueous and biological media using a batch process. The experimental conditions for efficient removal of TRB HCl for both CS and PUF were optimized depending on various experimental parameters such as the pH of the solution, contact periods, initial TRB HCl concentration, and sorbents dosage in the solution.</p><p>SEM, FT-IR, and XRD characterizations were carried out to study the adsorption of a drug by both sorbents. The optimum conditions for removing TRB HCl by CS and PUF were achieved at a pH of 8.5 and a contact time of 60 min at 250 rpm, using 0.4 g for both sorbents. The measured spectrophotometric absorbance at λ<sub>max</sub> of TRB HCl was 242 nm. In addition, the zero-point charge (pHpzc) was determined for the studied sorbents. The pHpzc of the surface of sorbents has shown that electrostatic attraction is one of the mechanisms in TRB HCl sorption. The adsorption process was modeled using the pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion kinetic models. The results indicated that the adsorption of TRB HCl on CS and PUF does follow a pseudo-first-order type of reaction kinetics. The adsorption process was modeled using Langmuir and Freundlich isotherms. The adsorption data found that the Freundlich isotherm model was more suitable for the PUF sorbent, while the Langmuir isotherm model better fit the CS biosorbent.</p><p>Evaluation of the experimental data using the Langmuir equation revealed that the maximum adsorption capacities of PUF and CS were 2.807 and 1.2297 mg. g<sup>-1</sup>, respectively. The solution was also used to estimate TRB HCl in its pharmaceutical form, and the assessed recoveries were 97.25 and 98.437% for CS and PUF, respectively. The proposed procedure was validated for other complex mediums by removing TRB HCl from spiked human blood plasma.<em> In-silico</em> aquatic toxicity forecast of TRB HCl was also carried out.</p>

Evaluation of MgO- and CaZrO3-promoted CaO-based pellets produced via solution combustion synthesis

Synthetic CaO-based sorbents stabilized with CaZrO3 and MgO were produced using a facile one-step fabrication procedure. Powdered sorbents were pelletized using two types of binders (calcium aluminate cement and boehmite) to shape the solids into forms suitable for reactor testing and evaluation under industrially relevant conditions. The CO2 uptake capacity and stability of pelletized sorbents were initially screened in a thermogravimetric analyzer, and subsequently assessed in a fixed and fluidized bed reactor. Sorbents showed a residual uptake capacity of 0.24 g/g after 100 cycles of carbonation and calcination in TGA, indicating a near threefold improvement over the residual CO2 uptake of natural Cadomin limestone (0.08 g/g). Similar improvements were observed when the sorbents were tested in a lab-scale reactor system, where the synthetic sorbents showed 0.4–0.45 g/g uptake after 5 cycles, whereas the uptake of Cadomin dropped to 0.15 g/g. Characterization of fresh and spent sorbents indicated an increase in the BET surface area of sorbents after cycling. Pore size distribution profiles exhibit increase of pore volume in the 20–100 nm region, whereas the pore volume in the < 6 nm region reduced. SEM images indicated formation of cracks after cycling, resulting from the expansion and contraction of sorbent over carbonation and calcination cycles.

Template synthesis of sulfur-doped mesoporous carbon for efficiently removing gas-phase elemental mercury from flue gas

Sulfur doped mesoporous carbon (SMC) was synthesized by using template method for efficiently removing gas-phase elemental mercury from flue gas. MCM-41 was used as sorbent template, and the mixture of thymol blue (C27H30O5S) and 2-thiophene ethanol (C6H8OS) was screened as co-precursor of carbon and sulfur. The mercury removal performance of the SMC was evaluated by fixed-bed mercury adsorption experiment. Effect of precursor ratio, carbonization temperature, adsorption temperature, and SO2 on mercury removal was studied. Combining with sorbent characterization, the mercury removal mechanism of the SMC was clarified. The results show that when the ratio of precursor (thymol blue: 2-thiophene ethanol) is 1:6 and the carbonization temperature is set at 900 ℃, the synthetic SMC-900 sorbent is a promising mercury sorbent, which displays excellent mercury removal performance as well as high SO2 tolerance. Decrease of carbonization temperature from 900 ℃ to 700 ℃ significantly reduces the mercury removal performance of SMC due to the incomplete carbonization of precursor. At 50–150 ℃, the mercury removal rate of SMC-900 is more than 97%, but a higher temperature inhibits its mercury removal capacity. The characterization result shows that the SMC-900 is spherical shape nanoparticle and the BET specific surface area reaches 933.0 m2/g. The mass proportions of carbon (C) and sulfur (S) of SMC-900 are 81.29% and 10.29%, respectively. The sulfur in SMC-900 is in the form of thiophene bond (C-S-C) and oxidized sulfur (C-SOx-C). In the presence of SO2, the main mercury removal product is HgS because the oxygen-containing functional group is occupied by SO2.

Sorption of silver (I) ions from aqueous solutions using the synthetic sorbent

We study the sorption of silver ions from aqueous solutions by a synthetic chelating sorbent. In the presence of formaldehyde, a polymeric sorbent based on a copolymer of styrene with maleic anhydride, modified with N,N’-diphenylguanidine, was synthesized and further used for extracting Ag(I) ions. The composition and structure of the synthesized polymeric chelating sorbent were studied using IR and UV spectroscopy methods. A simple, inexpensive, and efficient method for extracting Ag(I) ions from aqueous solutions was used. The effect of various parameters on the sorption process was studied, including the acidity of the medium (pH), the initial concentration of the metal ion, the time required to establish complete sorption equilibrium, and ionic strength. The optimum pH value for the extraction of Ag(I) was found to be 6. The process is characterized by a high adsorption capacity reaching 547.2 mg/g. The research results showed that the time required to establish a complete sorption equilibrium for the sorbent modified with N,N’- diphenylguanidine is 60 min. Ag(I) adsorption increases up to the value of ionic strength of μ = 1, after which its intensity decreases. At the final stage, the process of desorption of absorbed silver ions was carried out. During desorption, the best eluting agent for the extraction of Ag(I) was determined to be 0.5 M HNO3. The sorbent can be re-used after regeneration. The copolymer of styrene and maleic anhydride modified with N,N’-diphenylguanidine has a high sorption capacity and, therefore, can be used as a potential adsorbent for the extraction of silver (I) from aqueous solutions.

A Synthetic Analog of the Mineral Ivanyukite: Sorption Behavior to Lead Cations

The production of electrolytic nickel includes the stage of leaching of captured firing nickel matte dust. The solutions formed during this process contain considerable amounts of Pb, which is difficult to extraction due to its low concentration upon the high-salt background. The sorption of lead from model solutions with various compositions by synthetic and natural titanosilicate sorbents (synthetic ivanyukite-Na-T (SIV), ivanyukite-Na-T, and AM-4) have been investigated. The maximal sorption capacity of Pb is up to 400 mg/g and was demonstrated by synthetic ivanyukite In solutions with the high content of Cl− (20 g/L), extraction was observed only with a high amount of Na (150 g/L). Molecular mechanisms and kinetics of lead incorporation into ivanyukite were studied by the combination of single-crystal and powder X-ray diffraction, microprobe analysis, and Raman spectroscopy. Incorporation of lead into natural ivanyukite-Na-T with the R3m symmetry by the substitution 2Na+ + 2O2− ↔ Pb2+ + □ + 2OH− leds to its transformation into the cubic P−43m Pb-exchanged form with the empirical formulae Pb1.26[Ti4O2.52(OH)1.48(SiO4)3]·3.32(H2O).

Synthetic solid oxide sorbents for CO2 capture: state-of-the art and future perspectives

Solid oxides have been extensively investigated as possible high-temperature CO2 sorbents by a number of research groups. We summarised the different strategies to develop synthetic solid oxide sorbents.

Sorption of radioactive elements on synthetic sorbents

Sorption of radioactive elements on synthetic sorbents

Uranium sorption from waste solutions by Talc Phosphogypsum ferri-silicate synthetic new sorbent

Abstract In this investigation, a synthetic Talc Phosphogypsum ferri-silicate TPFS sorbent was prepared by thermal activation then evaluated the uranium ions removal from sulfate waste solution containing uranium. Generally, the synthetic adsorbents from raw and waste materials have a significant attention from scientists because the environmental concern and economic development, particularly, the uranium elimination from radioactive waste solutions. The uranium removal percentage and loading capacity were determined by optimization the conditions of adsorption such as the pH range, adsorbent/adsorbate ratio, uranium concentration of radioactive waste solutions, equilibrium time and temperature. The resultant adsorption efficiency and loading capacity were 87.2% and 375 mg g−1, respectively. The adsorption isothermally was in accordance with Langmuir isotherm model, in addition pseudo-second-order kinetic model, with theoretical capacity of 384.6 and 333 mg g−1, respectively. Uranium (VI) adsorption on TPFS was inhibited at elevated temperatures. The removal of uranium from sulfate waste solution by TPES sorbent according to the thermodynamic functions values was exothermic (∆H of −16.095) and non-spontaneous in nature (∆G of −17.27 at 303 K). In addition, there was a decrease in the randomness at the TPFS/uranium waste solution interface with ∆S value of 3.88.

Insight into the Sorption and Activation Energy Phenomenon of Kenaf Shive Sorbents in Crude Oil/Water Mixture

The secondary effect discovery of synthetic sorbents opened another research direction for many field of studies. However, the sorption parameters of lignocellulosic sorbents are rarely reported most importantly, kenaf shive. This paper centered at the sorption behavior of optimized kenaf shive sorbents using Response Surface Methodology (RSM) via surface deposit technique. Five-level Central Composite Design (CCD) experimental matrix was used to analyze the effect of particle sizes (125-1000 µm), stirring time (5-30min) and methyltrimethoxysilane (MTMS) concentration (5-20% v/v) as individual and combined variables process in the developed sorbents. The unmodified shive was compared with the modified, and it reveals a positive shift in the sorption capability. Instrumental analysis such as FTIR (Fourier Transform Infra-Red), DT-TGA (Differential Thermal-Thermogravimetric analysis) and BET (Brunaure-Emmett-Teller) were carried out on the optimized sorbent and the results were in conformity with the sorption results. The sorption behavior deployed fits the pseudo-first-order and Langmuir isotherm with regression coefficient R2=0.9496 and R2=0.9400. The sorption property was found to be spontaneous and exothermic, however, the activation energy studies shows physic-sorption phenomenon with 25.3 kJmol-1 and R2=0.9360.

Facile fabrication of porous waste-derived carbon-polyethylene terephthalate composite sorbent for separation of free and emulsified oil from water

Containment of oil spills in aquatic bodies and treatment of oily wastewater are necessary to mitigate oil pollution. Synthetic oil sorbents are commonly used for managing oil spills and while they are effective, their usage introduces a considerable amount of non-biodegradable plastic into the environment. In an effort to develop an inexpensive sorbent by reutilizing solid wastes for a sustainable future, this study investigates the fabrication of a composite oil sorbent from used polyethylene terephthalate bottles and waste carbonaceous residue from the gasification of oil refinery bottoms via an energy efficient phase inversion method. The composite sorbent demonstrated oil sorption capacity of ∼ 8 g/g, which is comparable to some commercially available adsorbents, and excellent retention capacity for mineral, paraffin and crude oils of different viscosities. Furthermore, the composite is able to remove oil from mineral or paraffin oil-in-water emulsions by sorption, with an efficacy of > 99.7 %, indicating its promising application in the treatment of industrial oily wastewater. Cost analysis shows that this waste-derived composite can be produced commercially at a competitive price.

ОЦІНКА СОРБЦІЙНОЇ ЄМНОСТІ МІНЕРАЛЬНИХ СОРБЕНТІВ ЩОДО FE(III) МЕТОДАМИ БАГАТОМІРНОГО КЛАСТЕРНОГО АНАЛІЗУ

The results of the study of the adsorption capacity of a number of sorbents of natural and synthetic origin with respect to iron ions have been clustered. The sorption capacity of the following sorbents was studied: natural zeolite of the Sokyrnytsia deposit, synthetic sorbent based on the ash of Doborotvir heat power plant, Al2O3, SiO2, as well as some types of soils: sandy soil, black soil and clay. Equations describing the regularities of adsorption processes depending on the type of sorbent are obtained. According to the obtained dendrograms of the adsorption process, two main clusters of sorbents were identified. The statistical parameters of the process and the significance of the obtained results are calculated. The coefficient of determination of experimental data was 0.87– 0.99, the standard deviation was 0.017–0.026.

Application of Copper Mining Waste in Radionuclide and Heavy Metal Immobilization

AbstractCopper slag flotation tailings (CSFT), as the end waste from copper mining, are evaluated for radionuclide and heavy metal immobilization. Characterization of CSFT based on grain size and mineral composition, surface functional groups, pH and electrical conductivity in aqueous media, thermogravimetric analysis (TGA), determination of characteristic temperatures in sample melting process, leachability, and toxicity tests is conducted. The screening sorption of Mn(II), Co(II), Ni(II), Zn(II), Cd(II), and Pb(II) inactive isotopes from single‐component solutions is performed. The Cd(II) ions show better sorption potential than other ions, with a sorption capacity of 0.08 mmol g−1 at the highest initial concentration. Sorption decreases in the sequence Cd(II) &gt; Pb(II) &gt; Zn(II) &gt; Mn(II) &gt; Ni(II) &gt; Co(II) at all initial concentrations. Although CSFT shows lower sorption capability than synthetic sorbents based on fayalite and magnetite, its inexpensiveness and substantial accessible amount represent great advantages in wider utilization.

Oil spill cleanup by natural fibers: a review

Purpose In recent years, oil spill pollution has become one of the main problems of environmental pollution. Recovering oil by means of sorbent materials is a very promising approach and has acquired more attention due to its high cleanup efficiency. Compared to synthetic fibrous sorbents, the use of natural fibers in oil spill cleanups offers several advantages including environmental friendliness, degradable features and cost-effectiveness. Therefore, studies on developing sorbents using natural fibers for oil spill cleanup applications have become a research hotspot. Design/methodology/approach This paper reviews the work conducted by several researchers in developing oil sorbents from fibers such as cattail, nettle, cotton, milkweed, kapok, populous seed fiber and Metaplexis japonica fiber. Some featured critical parameters influencing the oil sorption capacity of fibrous substrates are discussed. Oil sorption capacity and reusability performance of various fibers are also discussed. Recent developments in oil spill cleanups and test methods for oil sorbents are briefly covered. Findings The main parameters influencing the oil sorption capacity of sorbents are fiber morphological structure, fiber density (g/cc), wax (%), hollowness (%) and water contact angle. An extensive literature review showed that oil sorption capacity is highest for Metaplexis japonica fiber followed by populous seed fiber, kapok, milkweed, cotton, nettle and cattail fiber. After use, the sorbents can be buried under soil or they can also be burned so that they can be vanished from the surface without causing environmental-related issues. Originality/value This review paper aims to summarize research studies conducted related to various natural fibers for oil spill cleanups, fiber structural characteristics influencing oil sorption and recent developments in oil spill cleanups. This work will inspire future researchers with various knowledge backgrounds, particularly, from a sustainability perspective.

Synthesis of waste bagasse-derived Li4SiO4-based ceramics for cyclic CO2 capture: Investigation on the effects of different pretreatment approaches

The bagasse, which is a typical agricultural and forestry waste, was employed as the silicon source to produce Li4SiO4-based ceramics with superior CO2 sorption performance. It is found that the presence of impurities elements in the bagasse ash will bring complex side reactions and form side products during the sorbent preparation process, which are extremely harmful to the performance of the synthetic sorbent. Pretreatment has been considered as an effective approach to reduce the impurities elements. In this work, the effects and mechanisms of water/acid washing pretreatments on bagasse ash were firstly detailed investigate and compared. The results indicate that the hydrochloric acid washing pretreatment can effectively remove the residual metals (Ca, Fe, etc.) in the sample in addition to the water-soluble impurities (K, P, S, etc.). The maximum sorption capacity of sorbent synthesized by the acid washing pretreatment is about 0.32 g/g sorbent and the superior performance can be well maintained over 10 cycles. A novel technical route utilizing the ash from biomass power plants for in-situ CO2 capture has been developed, which has great potential for carbon capture in the future.