Kapok Fiber Research Articles

Nanocrystalline Cellulose from Kapok Fiber (Ceiba pentandra) and its Reinforcement Effect on Alginate Hydrogel Bead

AbstractKapok fiber (Ceiba pentandra) is a potential source of cellulose, but its utilization is still minimal. This study aims to isolate nanocrystalline cellulose (NCC) from kapok fibers using acid hydrolysis at various times and characterize its properties as reinforcement for alginate‐nanocrystalline cellulose (Alg‐NCC) hydrogel beads. NCCs are characterized using various techniques, and hydrogel beads are characterized by syneresis and strength (TPA). Variations in hydrolysis time cause changes in functional groups, decrease length and diameter, increase degree of crystallinity, and thermal stability. Nanocrystalline cellulose isolation from BKF by chemical hydrolysis is better done at 60% sulfuric acid concentration, for 50 min to produce a yield of 38.92%, L/d aspect ratio ranges from 8.53 to 12.23, degree of crystallinity 71.00%, and thermal stability with maximum degradation temperature 298.69 °C. The incorporation of NCC on the Alg hydrogel beads leads to increase hardness 67.70% and decrease syneresis 4.14%. Thus, NCC can be used as a reinforcement agent because it has been shown to improve the physical, mechanical, and thermal properties of Alg‐NCC hydrogel beads. Alg‐NCC hydrogel beads have the potential to be widely applied in various fields.

Effect of Oxidation Time on the Properties of Cellulose Nanocrystals Prepared from Balsa and Kapok Fibers Using Ammonium Persulfate.

This study aimed to evaluate the effect of ammonium persulfate’s (APS) oxidation time on the characteristics of the cellulose nanocrystals (CNCs) of balsa and kapok fibers after delignification pretreatment with sodium chlorite/acetic acid. This two-step method is important for increasing the zeta potential value and achieving higher thermal stability. The fibers were partially delignified using acidified sodium chlorite for four cycles, followed by APS oxidation at 60 °C for 8, 12, and 16 h. The isolated CNCs with a rod-like structure showed an average diameter in the range of 5.5–12.6 nm and an aspect ratio of 14.7–28.2. Increasing the reaction time resulted in a gradual reduction in the CNC dimensions. The higher surface charge of the balsa and kapok CNCs was observed at a longer oxidation time. The CNCs prepared from kapok had the highest colloid stability after oxidation for 16 h (−62.27 mV). The CNCs with higher crystallinity had longer oxidation times. Thermogravimetric analysis revealed that the CNCs with a higher thermal stability had longer oxidation times. All of the parameters were influenced by the oxidation time. This study indicates that APS oxidation for 8–16 h can produce CNCs from delignified balsa and kapok with satisfactory zeta potential values and thermal stabilities.

Thermal-insulating, flame-retardant and mechanically resistant aerogel based on bio-inspired tubular cellulose

Inspired by the tubular structures found in naturally occurring thermal-insulating materials, tubular cellulose aerogels with improved mechanical resistant, thermal-insulating and flame-retardant properties were prepared from kapok fibers via a facile process. In contrast to fragileness of traditional organic-inorganic composites, an optimized sample exhibited an ultra-high compressive strength of 32 MPa. The tubular structure of this material resulted in a 37.4 °C increase in heat preservation compared with that obtained from a pulp aerogel without this morphology. The H3PO4 decomposed from (NH4)2HPO4 in the formulation crosslinked the outermost cellulose fibers to generate a clay-reinforced dense carbon layer in conjunction with montmorillonite, which restricted the movement of flames and the outflow of volatile compounds. The gaseous voids of internal tubular fibers interrupted the heat transport pathways to inhibit thermal transmission and trapped combustible volatiles to reduce the penetration pressure experienced by the dense carbon layer greatly. The combined effects of the carbon layer and tubular structure effectively limited the transfer of heat, oxygen and volatiles, leading to non-combustion of the optimal sample. This study provided a cost-effective and facile approach to prepare of thermal-insulating, fire-safe and high-strength aerogel showing promising applications in exterior wall insulation and vehicle interior.

Bioinspired 3D hierarchical BSA-NiCo2O4@MnO2/C multifunctional micromotors for simultaneous spectrophotometric determination of enzyme activity and pollutant removal

Artificial self-propelled micro/nano-motors have emerged as a promising hot spot in the fields of water-body remediation and environmental protection. Herein, we report a novel multifunctional micromotors with dual enzyme-like activities for simultaneous colorimetric determination and removal of environmental contaminants. Thanks to the tubular morphology inherited from kapok fibers, these bovine serum albumin-functionalized NiCo2O4@MnO2/C (BSA-NiCo2O4@MnO2/C) micromotors with dual oxidase/peroxidase-like activity can move forward quickly in aqueous solutions via a bubble recoil mechanism, which can not only enhance the colorimetric sensing performance, but also improve the removal efficiency toward Cu2+ ion by enhancing the mass transfer both in the detection and catalytic degradation systems. Moreover, the unique 3D hierarchical architecture assembled by core-shell NiCo2O4 @MnO2 nanosheets and C microtubes can provide more accessible reactive sites and thus dramatically facilitate such detection process. In combination with the autonomous motility, intrinsic oxidase/peroxidase-like activities and precisely tuned hierarchical architecture, these automatic micromachines not only are able to detect Cu2+ selectively and sensitively with the limit of detection of 2.0 nM, but also quickly remove Cu2+ from wastewater with maximal adsorption capacity of 161.8 mg g−1. Furthermore, these micromotors exhibit excellent catalytic activity for the degradation of tetracycline hydrochloride. This multifunctional mobile platform will provide a new and promising strategy for the simultaneous detection and decontamination of poisonous metal ions and other pollutants in aqueous samples.

Phase change material based on polypyrrole/Fe3O4- functionalized hollow kapok fiber aerogel matrix for solar /magnetic- thermal energy conversion and storage

Thermal transfer enhanced multifunctional energy conversion form-stabilized composite phase change materials (PCMs) present attractive research prospects for the energy management materials. However, complicated preparation, unsatisfied heat storage capacity and limited thermal transfer enhancement restrict their application. In this work, high-performance thermal transfer enhanced composited PCMs are facilely prepared via integration of polypyrrole/Fe3O4- functionalized hollow kapok fiber (KF) aerogel supports with paraffin wax (PW). The prepared composite PCMs achieve high thermal storage density (melting enthalpy of 161.4 J/g for the PW load mass fractions of 88%), greatly enhancement of thermal conductivity (1.06 W/m K, 307% higher than pristine PW) and outstanding cycling thermal stability. The hollow kapok fiber aerogel supports prevent the leakage and improve loading amount, and also endow the renewable and pollution-free features for the composite PCMs, which provides great potential for the commercial application on a large scale. Simultaneously, the continuous polypyrrole (PPy) dual coating and Fe3O4 nanoparticles endow the composite PCMs not only with excellent thermal conductivity, but also with solar /magnetic- thermal energy conversion characteristics which enriches the energy storage source of the materials.

A Column Study on The Efficiency and Reusability of Kapok Fibre as Car Wash Wastewater Treatment

The car washing industry which consumes large amount of water produces Car Wash Wastewater (CWW) which were likely to exceeds the standard set in both Malaysia’s and Singapore’s regulation. Kapok Fibre (KF) is a natural adsorbing material which have large lumen and low density is believed to be able to act as an adsorbent to manage the CWW. This study was done to determine the characteristic of KF and CWW and investigate the efficiency of KF in treating CWW along with the reusability of KF through a column study with Organic Loading Rate (OLR) of 12.41g COD/L.day. The CWW contains a certain concentration of Chemical Oxygen Demand (COD, Oil and Grease (O&G), and Anionic Surfactant (AS) though the interaction between KF and AS is novel. KF found out to has the capability in removing COD, O&G, and AS up to 88.37%, 100%, and 83.8% respectively. However, in reusability experiment there is limitation to KF in which by exceeding the operation time to 600 minutes of treatment, the efficiency in removing COD, O&G, and AS were found to drop to 62.02%, 75%, and 55% respectively. This shows that KF could be an avant-garde, low-cost sustainable treatment to treat CWW instead of the conventional high cost and complex operating system.

Extraction of nanocrystalline cellulose from Kapok fiber as potential water-resistant composite

This study focused on synthesizing of nanocrystalline cellulose (NCC) from kapok fiber with the combination of chemical and mechanical methods. The as-synthesized NCC is used to produce nanocrystalline cellulose (NCC) paper. It was determined that the optimum condition to synthesis nanocrystalline cellulose (NCC) from kapok fiber using acid hydrolysis process treatment was at 45°C, 2 hours and 50% concentration of H 2SO 4. The particle size of the synthesized nanocrystalline cellulose (NCC) was 262.9 - 455.6 nm. The disappearance of peaks 1731.89, 1594.68, 1505.51 & 1240 cm -1 in the (FTIR) spectroscopy was related to the removal of non-cellulose component such as lignin and hemicellulose. Based on the contact angle, the value gained for that contact angle of the filter paper was increased from 29.650° to 40.261° and 32.002° due to presence of nanocrystalline cellulose (NCC) in the filter paper. It was determined that the modified filter paper with the nanocrystalline cellulose (NCC) had the highest water-resistances property and was considered the most hydrophobic of all the other papers.

Physicochemical properties of surface modified ZnFe2O4 nanocomposite incorporated with bio‐templated kapok fiber for photoelectrochemical application

Surface‐modified zinc ferrite nanocomposites were successfully prepared thru ultrasonic impregnation technique by taking kapok fiber as a bio‐template. This work demonstrates a fast preparation method to produce the bio‐templated ZnFe2O4 composite photocatalyst. The templating method for photocatalyst is favorable due to the benefit of a large surface area for solar harvesting activities in the photoelectrochemical (PEC) system. Comprehensive physicochemical analyses have successfully determined the unique properties of the prepared catalysts. The pure mimetic fibrous catalysts were successfully fabricated as photoelectrodes on the fluorine tin oxide substrate using electrophoretic deposition technique for PEC measurement. The ranging ratio of precursors used to prepare bio‐templated zinc ferrite catalysts shows an effect on their surface structure then influences the photocurrent density performance of PEC analysis. The ZF1 photoanode at 1:1 Zn/Fe ratio has generated the highest photocurrent density of 58 μA cm−2 at 0.7 V vs. Ag/AgCl compare to other samples in 0.5 M Na2SO4 electrolyte solution under 100 mW cm−2 light irradiation. The high photocurrent density was attributed to the enhancement in light‐harvesting properties, fine surface structure, and high charge transfer properties that correlate with the composite ratio's alteration. The bio‐templated zinc ferrite photocatalysts are a promising photoanode in PEC activities.

Visible light-induced photocatalytic and antibacterial activity of TiO2/polyaniline-kapok fiber nanocomposite

Anatase TiO2 nanoparticles with an average crystallite size of around 6.06 nm were successfully immobilized on the surface of polyaniline-coated kapok fiber (PANI-KpF) via hydrothermal reaction. The photocatalytic activity of the TiO2/PANI-KpF nanocomposite was studied under visible light using methyl orange (MO) and Cr(VI) as model pollutants. Photodegradation of MO was achieved using nanocomposites prepared with 0.5 and 1.0 mL titanium isopropoxide (TTIP) with removal efficiencies of about 87.4 and 76.8%, respectively. These are about 13 and 18% higher than the removal efficiencies under dark conditions. On the other hand, visible light-induced photo-reduction of Cr(VI) was carried out in the presence of isopropanol (IPA) as a hole scavenger, with 100% removal efficiency. Without IPA, Cr(VI) was removed by adsorption. The TiO2/PANI-KpF also showed antibacterial activity against E. coli bacteria under visible light.

Techno-economic and Environmental Analyses on Reduced Graphene Oxide modified Kapok Fiber as Oil Absorbent

The industrialization of synthetic fiber has resulted in an economic depression for both domestic and global kapok fiber industries as well as the farmers. On the other hand, the development of ssthe oleochemical industry in Indonesia demands a separation process that is less cost- and energy-intensive. Supporting the sustainable development goals (SDGs) number 1, 8, 9, 12, and 13, in this study, the under-tapped kapok fiber has been utilized to show its potential value as an oil sorbent material. Despite having high oil sorption capacity and being biodegradable, the raw kapok fiber has low oil selectivity, low oil retention, and a fragile structure. The kapok fiber has been modified with reduced graphene oxide (rGO) to obtain hydrophobic-oleophilic absorbent with high absorption capacity, high oil selectivity, high oil retention, and strong structure to maximize the recovery yield. Modification has been done by soaking kapok fiber in GO supernatant and reducing them with ascorbic acid, then freeze-drying the fiber to get a robust superhydrophobic sponge. Techno-economic and life-cycle analyses have been conducted and the results indicate that rGO-KF aerogel is economically viable with a potential GPM greater than 36,27%, and environmentally beneficial as it can potentially decrease product carbon emissions by 32.8 tons/ton recovered oil.

Study on the photocatalytic performance of TiO2 composited with Ag3PO4 based on biological template

The hollow tubular structure of kapok fiber was successfully replicated by using kapok fiber as a template through a high-temperature calcination method. The kapok fiber was treated as a photocatalytic carrier material, the photocatalytic performance of the samples that tubular TiO2 composited with Ag3PO4 prepared by the new method was discussed. It was found that Ag3PO4 particles with small particle size can be prepared through a simple stirring method at room temperature. Ag3PO4/TiO2 composite material can be obtained by an in-suit synthesis. The experimental results show that the Rhodamine B can be photodegraded completely by Ag3PO4/TiO2 composite within 60 min, the photodegradation of Ag3PO4/TiO2 is significantly better than the photocatalytic effect of pristine TiO2. After three cycles, the degradation rate can still achieve 100% within 60 min. The photogenerated carriers separation efficiency of Ag3PO4/TiO2 was improved by composite with Ag3PO4. Through the visible diffuse spectra (DRS), it is obvious that the Ag3PO4/TiO2 has strong absorption in the visible spectrum, and the photocatalytic performance of the sample is improved.

Synthesis of Kapok (<i>Ceiba pentandra</i>) Carbon Sponges for Recovery of Oil and Organic Solvents

Extensive processes and costly precursors for the fabrication of existing sorbents for oil spills urges to look for more renewable sorbent sources. In this work, hollow, tubular, cellulosic fibers (kapok, Ceibapentandra) were successfully converted to carbon sponges by pyrolysis at increasing temperature and time. Fourier Transform Infrared (FTIR) spectroscopy confirmed the complete carbonization of the kapok fibers at 800 °C. Scanning Electron Microscope (SEM) images revealed that the carbonized kapok fibers maintained their original tubular structures, suggesting high surface area. Water contact angle measurement showed improved hydrophobicity, with a maximum value of about 135°. The carbonized fibers were able to hold selected organic and oil solvents ranging from 16-20 times the weight of the fibers. The fiber pyrolyzed at 400 °C for 0.5 h showed the highest sorption capacity at 45.56 g/g for palm oil, almost matching that of raw kapok.

Parametric Study of the Adsorption of Pb (II) and Cr (VI) Ions on Modified PAN-Kapok Fibers

This paper presents a parametric study on the adsorptive property of NaOH-treated polyacrylonitrile (PAN)-kapok fibers for the removal of Pb (II) and Cr (VI) ions in aqueous solutions. Generally, the NaOH-hydrolyzed PAN-kapok favors the adsorption of Pb (II) compared to Cr (VI). The adsorption capacity was in the range of 41.67-83.33 mg/g as the initial Pb (II) concentration was increased from 50 to 100 ppm. Similarly, the adsorption capacity for Cr (VI) was from 8.24 to 15.81 mg/g as the initial concentration was raised from 50 to 150 ppm. The adsorption capacity was also enhanced by increasing the adsorbent dosage. Finally, uptake of Pb (II) at the early stages of the adsorption was fast, with adsorption capacity reaching ~120 mg/g.

Hydrothermal Synthesis of Binder-Free Kapok (<i>Ceiba pentandra</i>) Fiber Paper-NiCo<sub>2</sub>O<sub>4</sub> Supercapacitor Electrode

There is a need to address the gap between the theoretical benefits and cost-efficient production of supercapacitors in the market in order to sway the preference of the industry from the current perishable energy sources and storage. More extensive exploration of sustainable fabrication methods and materials used for renewable energy storage are just some of the factors that would decrease this gap. A binder-free supercapacitor electrode made of NiCo2O4 and carbonized kapok fiber paper (CKFP) was successfully fabricated by hydrothermal process at relatively low temperatures. NiCo2O4 urchin-like structures were deposited on the surface of carbon fiber paper (CFP) and CKFP. XRD analysis confirmed the successful conversion of kapok fiber paper to CKFP after pyrolysis, as well as the growth of pure spinel NiCo2O4 nanostructures on CFP and CKFP. The cyclic voltammetry curves showed that the CFP-NiCo2O4 prepared at 140 °C had the highest specific capacitance of 143.51 Fg-1 at 2 mVs-1. The CKFP-NiCo2O4 synthesized at the same temperature yielded slightly higher specific capacitance of 146.29 Fg-1 at 2 mVs-1, and 508 Fg-1 at 0.5 Ag-1.

Zeolite-fiber membrane enabling low-temperature combustion and high reduction of liquid wastes

Adsorbent-containing kapok fiber membranes with high burning rates were developed to remove radionuclides and toxicants from liquid wastes and reduce the total waste volume. The zeolite-fiber membranes were made from natural kapok fibers without allowing the formation of physical or chemical bonds with the zeolite powder. The desorption rate of the adsorbent powder was measured to be within 5% in the aqueous solution for four types of adsorbents with various micro sizes. The adsorption rate of non-radioactive cesium ions with and without the fiber membrane was measured to confirm the effect of the fiber membrane on the adsorption capacity of the adsorbent. Finally, the adsorbent-containing membranes were burned with a volume reduction of 82 wt% without volatilizing the adsorbed cesium at 300 °C.

Ceibapentandra (L.) Gaertn (Kapok) Seed Fibre as a Recycled Paper Reinforcement Pulp

The kapok (Ceibapentandra (L.) Gaertn) seed fibre is unicellular with length up to 35 mm, however, it is covered by a hydrophobic waxy layer that limits its application in paper production. In this study, the effect of various pulping methods namely mechanical, chemi-mechanical, semichemical and chemical pulping on kapok fibre properties was investigated. Each kapok pulp was then blended with the secondary fibre recovered from kraftliner board for handsheet making to examine their reinforcing ability on strength properties. The results showed that kapok mechanical pulps (with and without dewaxing (5% (v/v) diluted detergent) and chemimechanical pulp were unable to improve the strength properties of the handsheet. Kapok pulps chemically treated with 18–25% of sodium hydroxide gave a better effect on handsheet strength properties whilst fibre treated with 20% sodium hydroxide showing the highest increment. Although the reinforcing effect of the 4% native cooked starch was slightly higher than that of the 10% kapok pulp blended in recycled paper, the recycling potential of the latter was better as all strength properties retained unchanged after recycling. The findings indicated that kapok chemical pulp is a promising reinforcing fibre source with superior recycling potential.

Fabrication of kapok fibers and natural rubber composites for pressure sensor applications

Biomass-based composites are of immerse importance because they allow combining properties in ways that are not found in nature. This work reports facile routs to produce pressure sensor in large scale from biomass kapok fibers and natural rubber. Two different strategies were applied to introduce conductive elements into the pressure sensor and are systemically compared, which include carbonization of the tubular kapok fibers and coating the fibre with conductive polymer. When used as a pressure sensor, the kapok fiber and natural rubber-based composites can respond logarithmically to the loading in the compressive strain range of 0 ~ 15% with excellent recyclability. As a prototype of the concept for practical application, a weight scale was constructed using the kapok fiber and natural rubber-based composites and showed distinct weight-dependent resistance changes, being feasible for measuring weight within a certain weight range. Besides, the strategy based on conductive polymer enables the pressure sensor to be insulative at its original state and become conductive when pressed, hereby making the composite a potential pressure-sensing material and pressure-responsive circuit switch. This study provides a platform for developing biomass-based electronic pressure sensors.

PEG-filled kapok fiber/sodium alginate aerogel loaded phase change composite material with high thermal conductivity and excellent shape stability

Phase change materials (PCMs) need to improve thermal conductivity and maintain stability to meet actual application requirements. Here, a novel composite based on hydroxylated boron nitride (BN-OH) as a thermally conductive filler with superior thermal energy storage and shape stability is reported. By combining kapok fiber (KF) and sodium alginate (SA), lightweight KF/SA aerogels were fabricated, and their highly porous but durable three-dimensional networks benefit the encapsulation of polyethylene glycol (PEG) and prevent the leakage of PEG. PCMs are prepared by vacuum-assisted impregnating of PEG into the aerogels. The thermal conductivity of 0.684 W∙m−1∙K−1 at 10 wt% BN-OH is greatly improved because hydroxyl groups cannot only reduce interfacial thermal resistance but form secure thermal conductive networks. In addition, this novel PCMs possesses excellent shape stability and high latent heat of fusion, and the PCMs keep their shapes stable without any leakage even is compressed upon the melting point of PEG.

Superinsulating composite aerogels from polymethylsilsesquioxane and kapok fibers

A facile method to synthesize light weight thermally superinsulating composite aerogel is being presented here. A polymethylsilsesquioxane (PMSQ) – cellulose composite aerogel starting from a trifunctional precursor viz. methyltrimethoxysilane (MTMS) and kapok fibers have been synthesized. Kapok fibers have been employed as they have a homogeneous hollow structure and also possess intrinsic low density. A PMSQ-Kapok composite aerogel with a density as low as 0.053 gcm−3 with a thermal conductivity of 0.018 W m−1 K−1 in room conditions has been synthesized. Besides, a flexural strength (at maximum stress) of 108 kPa ± 21 has been obtained through three points bending test. All the composite aerogels are mesoporous as characterized by N2 sorption isotherms and hydrophobic as shown by sessile drop experiments. On comparison with the earlier reported works and with some of the commercially available aerogel composites, the current results seem promising. For demonstrating the real application purpose, thin composite aerogel sheets have also been synthesized which could be easily rolled/bended.

Temperature Effect on Oil Sorption and Wettability of Kapok Fiber

ABSTRACT Kapok fiber as a natural sorbent with excellent hydrophobic-oleophilic characteristic was studied. The effect of temperature on oil sorption behavior and wettability of kapok fiber powder was quantitatively evaluated by capillary rise method. Results showed that at the packing density of 0.1 g/cm3, the oil sorption capacity of kapok fiber powder presented only about 5% difference when the temperature ranged from 20°C to 90°C, with the values to engine oil, mineral oil, and PAO4 ranging from 10.96 to10.42 g/g, 10.73 to 10.18 g/g, and 10.25 to 9.89 g/g, respectively. However, the sorption coefficient which related to the sorption rate increased almost exponentially with the increasing of temperature. Then, the oil wettability of kapok fiber powder was further investigated from the perspective of contact angle. Nearly logarithmic increment in contact angle between the fiber powder and test oil was observed when higher temperature condition was applied, indicating that the enhancement of temperature apparently weaken the wettability of oil to solid powder. The adhesion work between fiber powder and oil was evaluated based on Young–Dupré equation, which suggested that higher temperature lead to lower adhesion work. Outcomes from this research are believed to provide importance reference for the usage of kapok fiber as sorbent when different temperatures are applied.