FTIR Test Results Research Articles

OPTIMALISASI SIFAT MEKANIK SERAT ALAM DARI SERBUK KAYU ULIN MELALUI TEKNIK PENGERINGAN SEBAGAI PENGUAT MATERIAL BIOKOMPOSIT ANJUNGAN KAPAL

Ironwood (eusideroxylon zwageri) is a type of wood that has great potential for industrial development. Currently, forest exploitation activities and the wood industry produce 30%-60% solid wood waste and have not been utilized optimally. One way to use it is to make composite materials. The purpose of this study was to determine the most optimal drying technique of ironwood powder, to provide information on the morphology, content and functional groups as well as the mechanical strength of the biocomposite with a volume fraction ratio. The ironwood powder samples in this study were characterized using the SEM-EDX, FTIR, and Vickers hardness tests. The results of the SEM test obtained information that the morphology of all samples had similarities, namely the surface was rough and the measured diameter of the sample ranged from 50-100 µm. While the EDX test obtained information that all samples had high carbon and oxygen content. The FTIR test results showed that ironwood powder had a cellulose content as evidenced by the absorption peaks and chemical bonds that were the same as pure cellulose. The results of the mechanical test on the biocomposite showed that sample C had the highest average HV value of 13.3 N/m2, while sample E had an average HV value of 12.26 N/m2 below the HV value of sample E. Meanwhile, sample A obtained the lowest hardness value with an average HV 5.93 N/m2.

High titanium heavy slag powder as a sustainability filler and its influence on the performance of asphalt mortar

High titanium heavy slag powder (HSP) is a typical waste with vast reserves but lacks effective disposal. This paper investigated for the first time the potential of reusing HSP as a sustainable mineral filler for asphalt mixtures. Firstly, a comprehensive comparison and analysis of the physicochemical properties of HSP and limestone powder (LSP) were conducted. Subsequently, asphalt mortars were designed, incorporating four filler-to-asphalt ratios (F/A of 0.2, 0.3, 0.4, 0.5) and five levels of HSP substitution for LSP (0%, 25%, 50%, 75%, 100%). Finally, selected properties of twenty types of asphalt mortar were tested. Compared with LSP, the HSP presented a coarser surface, more pores, smaller particle size and larger specific surface areas, which were conducive to the formation of more “structured asphalt”. Moreover, the chemical composition of HSP was complex, but it did not leach toxic elements, and the volume stability, high temperature stability, radioactivity met the requirements. However, its alkalinity was significantly lower than that of LSP, indicating weaker interactions with the asphalt. At F/A ratios of 0.2 and 0.3, the replacement of LSP with HSP resulted in a slight decrease in high temperature properties of asphalt mortars, but an improvement in low temperature performance. However, a further increase in the F/A ratio revealed an opposite trend. The properties of asphalt mortars were influenced by the combined effects of the chemical composition and physical properties of HSP. The FTIR test results indicated that no new functional groups were formed between the HSP and asphalt, suggesting primarily physical interactions.

Physical and chemical evaluation of adhesion recovery property of aged high-viscosity asphalt based on specialized composite rejuvenators

With the wide application of porous asphalt pavement, the techniques for recycling aged porous asphalt mixture have attracted more attention for facilitating its sustainable development. One of the most critical issues is how to recover the adhesion properties of aged high-viscosity asphalt (HVA). In this study, different specialized composite rejuvenators types on the adhesive properties of aged asphalt binder were designed and evaluated for the goal of adhesion recovery. A bond strength test was used to evaluate the macroscale adhesion properties between the regenerated asphalt and aggregate. Micro-scale chemical and physical tests were utilized to discover the regeneration mechanism of specialized composite rejuvenators on asphalt adhesion. The results showed that the proposed three kinds of composite rejuvenators can effectively restore and improve the adhesive properties of aged HVA. The results of differential scanning calorimetry (DSC) represented that recycled HVA with smaller Tg and total heat absorption showed better adhesion properties. The FT-IR and AFM test results showed that the adhesion of recycled HVA is highly correlated with the C–O functional group index and micro adhesion. In addition, the concave structure in the asphalt surface is more beneficial to improve the asphalt-aggregate interface bonding, and the scheme of adding 8% optimized rejuvenator based on graft co-polymerization had the best effect, which could be promoted for the future application in the recycling of HVA in porous asphalt pavement.

Addition of Anadara Granosa Shell Chitosan in Production Bioplastics

Bioplastics is a plastic composite material that can decompose quickly and is environmentally friendly when interacting with soil and microorganisms. The aims of the research are: to examine the optimal composition of bioplastics made from tapioca waste by adding blood clam shell chitosan and glycerol, to determine the quality of production bioplastics from tapioca waste with the addition of blood clam shell chitosan and glycerol, and to determine the chemical content of the clam shells. bioplastic function of tapioca with the addition of blood clam shell chitosan and glycerol. The method used is experimental. Production of bioplastic by mixing waste tapioca flour, chitosan, and glycerol with a composition of 65%:35%:5mL, 70%:30%:5mL, and 75%:25%:5mL and additional water. The sample was put into a water bath and stirred at a temperature of 80oC for 15 minutes. Bioplastics were printed in aluminum foil, dried at 100oC for 90 minutes and cooled at room temperature for 6 hours. Laboratory test samples with tensile strength, elongation at break, FTIR, and biodegradation tests according to SNI 7188.7:2016 in the category of bioplastic easily decomposed. The results of the tensile strength on PBA1 samples were 0.75 Mpa, PBA2 samples were 0.54 Mpa, and PBA3 samples were 0.34 Mpa. Test value for elongation at break the PBA1 sample is 23.68%, the PBA2 sample is 15.33%, and the PBA3 sample is 12.12%. The sample test results do not meet the quality standard value of SNI 7188.7:2016 for the bioplastic category. The optimal composition of bioplastics is found in the PBA2 sample using tapioca flour as raw material with chitosan and glycerol as much as 70%:30%:5mL with a tensile strength 0.54%, an elongation at break 15.33%, biodegradation of 43%, and has a bioplastic content with functional groups (C=C), (CO), (CH),(OH), (C=C), and (CH2)n in the FTIR test results.

Physico-Mechanical Optimization and Antimicrobial Properties of the Bionanocomposite Films Containing Gallic Acid and Zinc Oxide Nanoparticles.

The mechanical and physical properties of the bionanocomposite films based on κ-carrageenan (KC)-gelatin (Ge) containing zinc oxide nanoparticles (ZnONPs) and gallic acid (GA) were optimized using the response surface method, and the optimum amounts of 11.19 wt% GA and 1.20 wt% ZnONPs were obtained. The results of XRD, SEM, and FT-IR tests showed the uniform distribution of the ZnONPs and GA in the film microstructure, and suitable interactions between biopolymers and these additives, which led to increasing the structural cohesion of the biopolymer matrix and improving the physical and mechanical properties of the KC-Ge-based bionanocomposite. In the films containing gallic acid and ZnONPs, an antimicrobial effect was not observed against E. coli; however, the GA-loaded and optimum films show an antimicrobial effect against S. aureus. The optimum film showed a higher inhibition effect against S. aureus compared to the ampicillin- and gentamicin-loaded discs.

The Effect of Sorbitol on the Mechanical Properties of Temu Ireng Rhizomes (Curcuma Aeruginosa Roxb.) Starch Biodegradable Plastic

Biodegradable plastic is made by mixing from temu ireng rhizomes starch matrix, sorbitol as a plasticizer, and chitosan as a filler through the melt intercalation method. heating process at 800C and drying at 70oC. The results show that the addition of chitosan and sorbitol has an effect on the characteristics of the plastic. The best tensile strength results on biodegradable plastic with a mass composition of starch: chitosan 5:5 gram without the addition of sorbitol is 4.03 MPa. The best percentage of elongation in plastic with a composition of starch: chitosan 8:2 gr and 3 ml Sorbitol is 99.68%. The best water resistance to biodegradable plastic was the composition of starch: chitosan 5:5 gr without the addition of sorbitol is 83.33%. And the best biodegradability in plastic with a composition of 5:5 chitosan without the addition of sorbitol was 100% for 9 days. FTIR test results show that biodegradable plastic have the same wavelength as their constituent raw materials. This shows that the resulting film only interacts physically.

Effects of Al and Co doping on the structural stability and high temperature cycling performance of LiNi0.5Mn1.5O4 spinel cathode materials

The poor structural stability and capacity retention of the high-voltage spinel-type LiNi0.5Mn1.5O4 (LNMO) limits their further application. Herein, Al and Co were doped in LNMO materials for a more stable structure and capacity. The LNMO, LiNi0.45Al0.05Mn1.5O4 (LNAMO) and LiNi0.45Co0.05Mn1.5O4 (LNCMO) were synthesized by calcination at 900 °C for 8 h, which was called as solid-phase method and applied universally in industry. XRD, FT-IR and CV test results showed the synthesized samples have cation disordering Fd-3m space group structures. Moreover, the incorporation of Al and Co increased the cation disordering of LNMO, thereby increasing the transfer rate of Li+. The SEM results showed that the doped samples performed more regular and ortho-octahedral. The EDS elemental analysis confirmed the uniform distribution of each metal element in the samples. Moreover, the doped samples showed better electrochemical properties than undoped LNMO. The LNAMO and LNCMO samples were discharged with specific capacities of 116.3 mA·h·g−1 and 122.8 mA·h·g−1 at 1 C charge/discharge rate with good capacity retention of 95.8% and 94.8% after 200 cycles at room temperature, respectively. The capacity fading phenomenon of the doped samples at 50 °C and 1 C rate was significantly improved. Further, cations doping also enhanced the rate performance, especially for the LNCMO, the discharge specific capacity of 117.9 mA·h·g−1 can be obtained at a rate of 5 C.

Development of cell adhesive and inherently antibacterial polyvinyl alcohol/polyethylene oxide nanofiber scaffolds via incorporating chitosan for tissue engineering

Currently, polyvinyl alcohol (PVA) and polyethylene oxide (PEO), as tissue engineering scaffolds materials, had been widely studied, however the hard issues in cell adhesive and antimicrobial properties still seriously limited their application in biomedical respects. Herein, we solved both hard issues by incorporating chitosan (CHI) into the PVA/PEO system, and successfully prepared PVA/PEO/CHI nanofiber scaffolds via electrospinning technology. First, the hierarchical pore structure and elevated porosity stacked by nanofiber of the nanofiber scaffolds supplied suitable space for cell growth. Significantly, the PVA/PEO/CHI nanofiber scaffolds (the cytotoxicity of grade 0) effectively improved cell adhesion by regulating the CHI content, and presented positively correlated with the CHI content. Besides, the excellent surface wettability of PVA/PEO/CHI nanofiber scaffolds exhibited maximum absorbability at a CHI content of 15 wt%. Based on the FTIR, XRD, and mechanical test results, we studied the semi-quantitative effect of hydrogen content on the aggregated state structure and mechanical properties of the PVA/PEO/CHI nanofiber scaffolds. The breaking stress of the nanofiber scaffolds increased with increasing CHI content, and the maximum value reached 15.37 MPa, increased by 67.61 %. Therefore, such dual biofunctional nanofiber scaffolds with improved mechanical properties showed great potential application in tissue engineering scaffolds.

Feasibility study of microplastic biodegradation in effluents from South Tehran WWTP after quantitative and qualitative measurement of the particles

Microplastics are currently known to be among the most detrimental environmental. The research on ways to counteract these pollutions and the use of microorganisms for the biological decomposition of various plastic polymers have evolved over the recent years. In this regard, the present study collected effluents from the southern Tehran treatment plant and separated and counted the microplastics present in them, it was found that the least number of microplastics was found in the samples of the summer season and the highest number of microplastics was found in the samples of the spring season. In these samples, particles could be identified in three forms: fiber, fragment, and film, which revealed that the most frequently observed microplastics were polypropylene and then polyethylene. These microplastics combine with the microbes in the culture medium. Three microbial colonies that survived were then separated and identified, which revealed that these bacteria included Achromobacter denitrificans (sample B), Bacillus amyloliquefaciens (sample C), and Pseudomonas aestusnigri (sample E). Moreover, the decomposition of polypropylene and polyethylene microplastics exposed to isolates was examined through various methods. Results of cellular gravity examination indicated that the average weight reduction in the PP sample exposed to B and E bacterial isolates was 38.2% and 58.9%, respectively. In the SEM images, the surface of the polymers of these two isolates is more uneven. Moreover, the mean cellular weight reduction for PE-based microplastic exposed to isolate C was 13.3%, the results of FT-IR tests showed that the peaks in the samples exposed to strains B and E were accompanied by changes compared to the control sample (G). The results of the TGA test also confirm the greater effectiveness of the bacterial strain E. It was based on the polymer structure. In the Raman spectrum of sample E, some peaks have been removed and new peaks with other shifts have appeared in their place. Results were confirmed by carbon dioxide emission tests and the produced protein amount.

Effect of Potassium Peroxodisulphate and Microwave Power on Hydrogel Character Based on Banana Peel Waste Using Microwave Grafting Method

<p><em>Musa paradisiaca var. raja</em> peel waste contains cellulose which has the potential to be a raw material for synthesizing hydrogels. This research utilizes acrylamide monomer grafted onto banana peel cellulose backbone using the microwave grafting method to produce hydrogel. The banana peel waste was dried to a constant weight and then crushed into powder. Banana peel powder was through a delignification process with the addition of NaOH and bleached with NaClO to took only the cellulose of the banana peel. The mixture of banana peel cellulose-acrylamide-potassium peroxodisulfate powder through the grafting process was repeated with variations in KPS concentration and microwave power. The reaction was terminated with a hydroquinone solution, washed with acetone, and then precipitated. The precipitated solid was dried to a powder called cellulose-g-PAAM. A homogeneous solution of 2% carrageenan-cellulose-g-PAAM underwent a physical crosslinking process using KCl and CaCl<sub>2</sub> solutions after passing through palm oil to form a bead gel. The purpose of this research was to determine the effect of potassium peroxodisulfate (KPS) initiator concentration and microwave power on the swelling capacity in water. The properties of obtained dried bead gels were characterized their functional groups using FTIR and swelling capacity test in water. From this research, it can be concluded that banana peel cellulose was successfully grafted onto acrylamide monomer as evidenced by the FTIR test results. The lower KPS concentration is the greater on the swelling capacity and the microwave power has no effect on the swelling capacity of bead gels.</p><p><strong>Keywords: </strong>Banana peel, Bead gel, Microwave, Swelling degree </p>

Analysis of Coal Boiler Ash Content and Palm Shell Boiler Ash as a Cementitious Material in ECC Mortar

XRF characterization results showed that coal boiler ash contained SiO2 = 29.3%; Al2O3= 14%; Fe2O3= 30.9%; CaO= 18.3% and palm shell boiler ash containing SiO2 = 48.9%; Fe2O3= 3.42%; CaO= 13.8%. The FTIR test results show that the OH stretching vibration of the SiOH group absorbs in the regions 3676, 3597, 3462, and 3315 cm-1 at the peak of the coal boiler ash spectrum and 3614, 3502, 3365, and 3323 cm-1 at the peak of the palm shell boiler ash spectrum. From the ECC mortar FTIR test results, it can be seen that the functional group changes with the OH stretching vibration of the SiOH group absorbing in the 3387 cm-1 area. The results of the ECC mortar compressive strength test at 28 days increased with the addition of coal boiler ash up to 15% and palm shell boiler ash 10%, so the compressive strength was 59.30 MPa.

Effect of delignification and bleaching stages on cellulose purity of oil palm empty fruit bunches

Oil palm empty fruit bunches (OPEFB) have not been properly utilized by most palm oil mills and communities in Indonesia. The processing and utilization of OPEFB by palm oil mills are still limited. Due to high cellulose contents, it potentially made into various bioproducts, especially as biomaterials. Therefore, a proper extraction technology is needed to obtain a high level of cellulose purity because alkaline treatment can solely remove a part of hemicellulose and lignin. A higher cellulose content can be obtained by further chemical treatments through the bleaching process. However, no information regarding the difference of the isolation performance method to produce cellulose purity by delignification first or vice versa bleaching as an initial stage. The research determined the purity of EFB cellulose with differences in the sequence of bleaching and alkaline delignification stages. The three methods were carried, namely the first method by bleaching using sodium chlorite 3% two times, followed by delignification of NaOH 10% at room temperature, second method with the same conditions but delignification of NaOH 10% at a temperature of 70-80°C and third method by delignification and continued bleaching under the same conditions. The results showed the bleaching method of sodium chlorite of 2 cycles and continued by alkaline delignification (NaOH 10%) at room temperature resulted in higher cellulose purity than other methods. The FTIR test results indicated the detection of the C-O functional group at a wavelength of 1196 cm-1 and the C-H functional group at a wavelength of 2967 cm-1.

Insight into pyrolysis of hydrophobic silica aerogels: Kinetics, reaction mechanism and effect on the aerogels

Silica aerogels have promising applications in thermal insulation, but their flammability and reaction mechanisms have rarely been investigated. The pyrolysis kinetics and thermodynamics of hydrophobic silica aerogels under N2 environment were studied. The kinetic and thermodynamic parameters were obtained by three model-free methods. Based on the calculated kinetic parameters, the pyrolysis mechanism of silica aerogels was discussed by the master plots method. The results indicate that the reactions of the whole pyrolysis phase can be characterized by a random nuclear model. In addition, FTIR test results show that the volatile products of silica aerogel pyrolysis are mainly hydrocarbons generated by the decomposition of hydrophobic groups (methyl groups) on the surface. Finally, the effects of pyrolysis on the properties of silica aerogels Finally, the effects of pyrolysis on the properties of silica aerogels were investigated based on the analysis results of SEM, specific surface area, pore size distribution, X-ray diffraction, XPS and infrared spectroscopy.

Development of Environmentally Friendly Wool Shrink-Proof Finishing Technology Based on L-Cysteine/Protease Treatment Solution System.

The particular scale structure and mechanical properties of wool fiber make its associated fabrics prone to felting, seriously affecting the service life of wool products. Although the existing Chlorine-Hercosett treatment has a remarkable effect, it can lead to environmental pollution. Therefore, it is of great significance to develop an environmentally friendly and effective shrink-proof finishing technology. For this study, L-cysteine was mixed with protease to form a treatment solution system for shrink-proof finishing of wool fibers. The reduction performance of L-cysteine and its effect on wool were compared with those of other reagents, demonstrating that L-cysteine has an obvious reduction and destruction effect on the wool scale layer. Based on this, L-cysteine and protease 16L were mixed in a certain proportion to prepare an L-cysteine/protease treatment solution system (L/PTSS). The shrink-proof finishing of a wool top was carried out by the continuous multiple-padding method, and the processing parameters were optimized using the response surface method. The results indicated that when the concentrations of L-cysteine and protease 16L were 9 g/L and 1 g/L, respectively, the wool was padded five times at 50 °C, and each immersion time was 30 s, the felt ball density of the treated wool reduced from 135.86 kg/m3 to 48.65 kg/m3. The structure and properties of the treated wool were also characterized using SEM, TG, and tensile strength tests, which indicated that the fiber scale structure was stripped evenly. Meanwhile, the treated fibers still retained adequate thermal and mechanical properties, indicating suitable application value. XPS, FT-IR, Raman, UV absorbance, and other test results revealed the reaction mechanism of L/PTSS with the wool fibers. After L-cysteine rapidly reduced the disulfide bonds in wool, protease can hydrolyze peptide chains more effectively, causing the scale layer to gradually peel off. Compared with the chlorination method and other protease shrink-proof technologies, L/PTSS can achieve the finishing effect on wool rapidly and effectively, without causing excessive pollution to the environment. The conclusions of this study provide a foundation for the development and industrial application of biological enzyme shrink-proof finishing technology.

Preparation of Mullite/PU Nanocomposites by Double Waste Co-Recycling

The massive accumulation of industrial waste has become an environmental problem that is very difficult to deal with. In this paper, mullite whisker nanomaterials were developed independently using industrial waste residues, which were used to degrade polyurethane (PU) solid waste by alcoholysis with ethylene glycol (EG) and ethanolamine (ETA) bi-component, and mullite modified regenerated polyol materials were obtained by double waste synergistic recycling. Mullite/PU foam nanocomposites were prepared by one-step foaming. The analysis of the test results shows that, at EG/ETA = 2:1 and mullite whisker addition of 0.15%, the regenerated rigid PU foam obtained has low thermal conductivity and higher compressive strength, at which time the regenerated PU foam has the best performance. The FTIR test results show that the silanol of mullite reacts with isocyanate during foaming and is attached to the polyurethane chain, such that the compressive strength and thermal insulation properties are maximized. It provides a new way to create a “double waste synergy” for preparing high-value materials by comprehensively utilizing resources.

Preparation and Characteristics of Na2HPO4·12H2O-K2HPO4·3H2O/SiO2 Composite Phase Change Materials for Thermal Energy Storage.

In this paper, a series of eutectic hydrated salts was obtained by mixing Na2HPO4·12H2O (DHPD) with K2HPO4·3H2O (DHPT) in different proportions. With the increase in the content of DHPT, the phase transition temperature and melting enthalpy of eutectic hydrated salts decreased gradually. Moreover, the addition of appropriate deionized water improved the thermal properties of eutectic hydrated salts. Colloidal silicon dioxide (SiO2) was selected as the support carrier to adsorb eutectic hydrated salts, and the maximum content of eutectic hydrated salts in composite PCMs was 70%. When the content of the nucleating agent (Na2SiO3·9H2O) was 5%, the supercooling degree of composite PCMs was reduced to the minimum of 1.2 °C. The SEM and FT-IR test results showed that SiO2 and eutectic hydrated salts were successfully combined, and no new substances were formed. When the content of DHPT was 3%, the phase transition temperature and melting enthalpy of composite PCMs were 26.5 °C and 145.3 J/g, respectively. The results of thermogravimetric analysis and heating-cooling cycling test proved that composite PCMs had good thermal reliability and stability. The application performance of composite PCMs in prefabricated temporary houses was investigated numerically. The results indicated that PCM panels greatly increased the Grade I thermal comfort hours and reduced energy consumption. Overall, the composite PCM has great development potential building energy conservation.

Facile fabrication of Fe/Zr binary MOFs for arsenic removal in water: High capacity, fast kinetics and good reusability

A water-stable bimetallic Fe/Zr metal-organic framework [UiO-66(Fe/Zr)] for exceptional decontamination of arsenic in water was fabricated through a facile one-step strategy. The batch adsorption experiments revealed the excellent performances with ultrafast adsorption kinetics due to the synergistic effects of two functional centers and large surface area (498.33 m2/g). The absorption capacity of UiO-66(Fe/Zr) for arsenate [As(V)] and arsenite [As(III)] reached as high as 204.1 mg/g and 101.7 mg/g, respectively. Langmuir model was suitable to describe the adsorption behaviors of arsenic on UiO-66(Fe/Zr). The fast kinetics (adsorption equilibrium in 30 min, 10 mg/L As) and pseudo-second-order model implied the strong chemisorption between arsenic ions and UiO-66(Fe/Zr), which was further confirmed by DFT theoretical calculations. The results of FT-IR, XPS analysis and TCLP test demonstrated that arsenic was immobilized on the surface of UiO-66(Fe/Zr) through Fe/Zr-O-As bonds, and the leaching rates of the adsorbed As(III) and As(V) from the spent adsorbent were only 5.6% and 1.4%, respectively. UiO-66(Fe/Zr) can be regenerated for five cycles without obvious removal efficiency decrease. The original arsenic (1.0 mg/L) in lake and tap water was effectively removed in 2.0 hr [99.0% of As(III) and 99.8% of As(V)]. The bimetallic UiO-66(Fe/Zr) has great potentials in water deep purification of arsenic with fast kinetics and high capacity.

Effect of porous carbon on thermal and physical properties of composite pure alkane/expanded vermiculite phase change energy storage materials

Nine kinds of mixed N-alkanes with different proportions were prepared by mixed eutectic method. A set of ratios with enthalpy values up to 289.8 J/g were selected for encapsulated PCM. Using potato starch solution with a concentration of 30 % as porous carbon source, the heat transfer capacity of expanded vermiculite was enhanced by modification between expanded vermiculite channels, and matrix coated phase change material was prepared. SEM images show that the PCM are successfully adsorbed in the pores. The latent heat and temperature of phase change in the melting and solidification process are 208.1 J/g and 21.2 °C, 203.11 J/g and −3.4 °C, respectively. FT-IR, XRD, TGA and thermal cycling test results show that phase change energy storage particles have good thermal performance. Therefore, the prepared materials have excellent properties.

Characteristics of Chitooligosaccharides Hydrolysate from Crab Shell (Portunus Pelagicus) Waste by Chitosanase Hydrolysis

Enzymatic hydrolysis of chitooligosaccharides can be carried out using the chitosanase enzyme. Chitosanase enzyme is a glycosyl hydrolase enzyme that catalyzes the hydrolysis of β- 1,4 glycosidic bonds of chitosan to produce low molecular weight chitooligosaccharides. The crab shell (Portunus pelagicus) has the potential to be used as chitooligosaccharides because the crab shell contains 20-30% chitin. This study aimed to determine the effect of chitosanase enzyme concentration and duration of hydrolysis on the characteristics of chitooligosaccharides (COS) from crab shells. This research was conducted using a factorial completely randomized design (CRD) method with two factors and two replications. The factor I was enzyme concentration (0.5%, 1%, and 1.5%), factor II was hydrolysis time (3 hours, 4 hours and 5 hours). The data were obtained using ANOVA if there was a significant difference, followed by Duncan's Test (DMRT). The best results were obtained in the A2B2 treatment, enzyme concentration (1.0%) and hydrolysis time (4 hours) with a chemical composition of 84.96% yield, 4.83 KDa molecular weight, 86.87% degree of deacetylation and FTIR test results indicated the availability of a functional groups, the OH group was obtained at a wavelength of 3624.25 cm-1 and the NH group is at a wavelength of 3404.36 cm-1.

Characterization of Spent Coffee Grounds in the Community as Supporting Materials for Renewable Energy

Coffee grounds are a by-product of the coffee brewing process. Currently, coffee grounds in the community are still untapped waste. Whereas spent coffee grounds has the potential to be converted into various high value bio-products that are environmentally friendly. This study aims to characterize coffee grounds waste which is popular in the community as a supporting material for renewable energy. This study uses a comparative method of 3 samples of Arabica coffee grounds (SCG-A), Robusta (SCG-R), and the Arabica-Robusta blend (SCG-AR) from coffee brands that are popular in Indonesian. Quantitative analysis was carried out by comparing the percentage of residual yield of the three samples. Qualitative characterization of coffee grounds was carried out using the FTIR 8300/8700 Spectrophotometer. The results of the three samples showed different rendemen values, namely 70% SCG-A, 60% SCG-R, and 80% SCG-AR. The FTIR test results showed that the three spent coffee grounds had the same functional group characteristics in the frequency range of 650–3900 cm-1. The detection of the hydroxyl functional group (-OH), the asymmetric strain of the CH bond of the methyl group (-CH3), and the stretching vibration of CO in the COH bond found in coffee grounds waste shows its potential as a supporting material for renewable energy if a further process is carried out in the form of pyrolysis/calcination at room temperature. 700◦C. Utilization of spent coffee grounds in the community can be done by establishing a Spent Coffee Grounds Bank (SCG Bank), educating the public so that they are willing to donate spent coffee grounds, and managing SCG as a supporting material for renewable energy.