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Penggunaan membran padat kitosan-silika-polietilen glikol (Ch/Si/P) sebagai membran pemisah telah dipelajari. Dalam penelitian ini, membran padat kitosan-silika-polietilen glikol digunakan sebagai membran pemisah untuk ion logam bivalen, termasuk Pb(II), Cu(II), Cd II), dan zat warna Rhodamin B dalam limbah cair tekstil. Membran padat Ch/Si/P dibuat dengan mencampurkan kitosan, silika (dengan natrium silikat yang diisolasi dari abu sekam padi sebagai sumber silika) dan polietilen glikol dengan perbandingan 1: 0,8: 0,5 (b/b). Uji kinerja membran padat dilakukan menggunakan metode dead-end. Uji kinerja menunjukkan bahwa selektivitas membran padat Ch/Si/P meningkat dari Cu(II)> Cd(II)> Pb(II)> Rhodamine B. Membran komersial menunjukkan, selektivitas mengikuti urutan Rhodamine B> Pb(II)> Cd(II)> Cu(II). Hasil penelitian menunjukkan bahwa membran padat Ch/Si/P lebih baik sebagai membran pemisah ion logam bivalen dibandingkan membran komersial. Membran komersial lebih baik sebagai membran pemisah Rhodamine B dibandingkan membran padat Ch/Si/P karena memiliki struktur berserat dan berpori.

Chitosan is interestingly thought to be used as raw material to make membrane for it has functional group of –NH2 and –OH that is easy to modify. Chitosan membrane has weakness like low mechanical properties. To overcome those weaknesses, silica is added on chitosan membrane synthesis to improve chitosan membrane stability. In membrane synthesis process, plasticizer is used to improve mechanical properties, maintain integrality, and avoid holes and crackness. Polyethylene Glycol plasticizer addition is expected to increase physical and mechanical properties and hydrophilic properties on membrane surface significantly therefore metal ion solution can easily diffuse through chitosan-silica-PEG membrane. In this research, it is done chitosan-silica-PEG (Ch/Si/P) membrane synthesis with tetraethyl orthosilicate (TEOS) that is used as silica source then the membrane is used as adsorbent for ion Cu(II), Zn(II) and Cd(II) by batch method. Research shows that adsorption with batch method to all membranes is optimum pH for metal ions Cu(II) and Zn(II) = 6, Cd(II) = 5.5. Adsorption for ions Cu(II), Zn(II) and Cd(II) in membrane tends to follow Langmuir isotherm model. Generally, it can be said that Ch membrane ability on all adsorption metal ions increases with silica or PEG addition. Adsorption capacity value for Ch/Si/P membrane in \(\mu\)mol/g for ion Cu(II), Zn(II) and Cd(II) in order are 262, 183, and 107 \(\mu\)mol/g. Generally, in adsorption kinetic data there is a tendency of coefficient score of R2 linearity that is higher in the second order of pseudo kinetic model.

Palm Oil Fuel Ash (POFA) is produced from the burning of palm oil solid waste biomass. POFA is abundant in Indonesia considering that Indonesia is one of the world’s largest producers of Crude Palm Oil (CPO) and has the largest palm oil plantation. The main content of POFA is SiO2 around 60%, Al2O3 around 3-10% and CaO around 5-15% so that POFA has the potential to be developed as aluminosilicate inorganic polymers. The high SiO2/Al2O3 ratio in POFA needs to be reduced for the formation of Si-O-Al chains in geopolymers. Therefore, two stages of research were carried out. Preliminary research was conducted to obtain optimum Solid/Liquid ratio. Aluminum powder was then added with certain variations to get a certain SiO2/Al2O3 ratio as well as a foaming agent so that the product can later be used as a porous building material. The preliminary results showed that the optimum Solid/Liquid ratio obtained was 0.83. The addition of aluminum powder was optimum at 2% w/w with a compressive strength of 5.4233 MPa, a density of 1339.2175 kg/m3, and a thermal conductivity of 0.6233 Watt/m°K. This geopolymer product can be categorized as a lightweight building material with criteria: a compressive strength of 0.5-10 MPa, densities between 600-1800 Kg/m3, and a thermal conductivity of 0.1-0.7 Watt/m°K which can be used as panels in buildings, casting walls, and ornaments in parks.

Telah dilakukan ekstraksi pektin dari belimbing wuluhdengan variasi suhu ekstraksi 60 dan 100C, serta variasi waktu ekstraksi 30, 60, 90 dan 120 menit.Penelitian ini bertujuan untuk mengetahui suhu dan waktu ekstraksi terbaik. Proses ekstraksi dengan metode refluks menggunakan air destilatyang telah ditambahkan dengan asam klorida. Proses selanjutnya adalah pengendapkan,pencucian dan pengeringan. Pektin yang dihasilkan dianalisis kemudian pektin terbaik dipilih menggunakan perhitungan metode Bayes. Kondisi ekstraksi pektin terbaik adalah pada suhu 100C dengan waktu ekstraksi 30 menit dengan karakteristik sebagai beerikut: rendemen 0,38%, kadar abu 2,92%, kadar air 25,40%, berat ekivalen 650,77%, kadar metoksil 5,01%, kadar galakturonat 55,51%, derajat esterifikasi 51,25% dan viskositas 22cP. Pektin hasil ekstraksi terbaik telah memenuhi standarInternational Pectin Producers Assosiation (IPPA). Pektin terbaik memiliki warna coklat yang lebih gelap dibandingkan dengan pektin komersial. Hasil analisis FT-IR menunjukkan pektin terbaik dan pektin komersial keduanya mengandung gugus fungsi O-H, C-H alifatik, C=O, CH3, dan C-O.

Pineapple crown leaf was successfully converted to the magnetized activated carbon (MAC) as an attractive solution to overcome separation problems. The activated carbon (AC) was produced by an innovative method combining KOH activation and microwave heating while the magnetization process was prepared by a co-precipitation method. In this sense, the activation stage was studied at different impregnation ratio. The resulted magnetic adsorbent was further tested its feasibility for methyl violet dye removal. The result shows that MAC consists of both micropores and mesopores with more oxygen-containing functional groups, indicating it can be used to remove dye from contaminated water. The increase of impregnation ratio led to an increase in the MAC porosity and a decrease in the magnetic property. The adsorption behavior of methyl violet dye onto MAC was well described by the Redlich-Peterson isotherm model.

The adsorption of a solution mixture of Rhodamine B, Pb (II), Cu (II) and Zn(II) was studied using dynamic methods employing chitosan-silica-polyethylene glycol (Ch/Si/P) composite membrane as an adsorptive membrane. The composite Ch/Si/P membrane was prepared by mixing a chitosan-based membrane with silica isolated from rice husk ash (ASP) and polyethylene glycol (PEG) as a plasticizer. The resultant composite membrane was a stronger and more flexible membrane than the original chitosan-based membrane as indicated by the maximum percentage of elongation (20.5 %) and minimum Young's Modulus (80.5 MPa). The composite membrane also showed increased mechanical and hydrophilic properties compared to the chitosan membranes. The membrane was used as adsorption membrane for Pb (II), Cu (II), Cd (II) ions and Rhodamine B dyes in a dynamic system where the permeation and selectivity were determined. The permeation of the components was observed to be in the following order: Rhodamine B > Cd (II) > Pb (II) > Cu (II) whereas the selectivity was shown to decrease the order of Cu (II) > Pb (II) > Cd (II) > Rhodamine B.

Chitosan has been widely used as polymer matrix for Polymer Electrolyte Membrane (PEM) application replacing Nafion which has shortcomings in terms of high methanol permeability that degrades the performance of fuel cells. Chitosan membranes modification is performed by adding nanosilica to prevent methanol transport through the membrane. Nanosilica is synthesized by sol-gel method and the particle diameter is obtained by analysis using Breunner Emmet Teller (BET) that is 6.59 nm. Nanosilica is mixed with chitosan solution to obtain nanosilica-chitosan as polymer electrolyte membrane. The membranes are synthesized through phase inversion method with nanosilica composition including 0; 0.5; 1; 2; 3; 5; and 10% w/w of chitosan. Characterization of the membranes indicate that the results of water swelling, proton conductivity and methanol permeability of the membrane with 3% nanosilica respectively were 49.23%, 0.231 S/cm, and 5.43 x 10−7 cm2/s. Based on the results of membrane selectivity calculation, the optimum membrane is the composition of 3% nanosilica with value 5.91 x 105 S s cm−3. The results of functional groups analysis with FTIR showed that it was only physical interaction that occurred between chitosan and nanosilica since no significant changes found in peak around the wave number 1000-1250 cm−-1.

In this research, chitosan/silica/polyethylene glycol (Ch/Si/P) composites membrane was studied for selective adsorbent of Pb(II) from aqueous solution. This study started by preparation of Ch/Si/P composites membrane. The structure and surface morphology of Ch/Si/P composites membrane was characterized by X-ray diffraction (XRD), Fourier Transform Infra Red (FTIR) spectroscopy, and Scanning Electron Microscopy (SEM). Batch adsorption experiments were conducted with various contact time and Pb(II) concentrations to evaluate the adsorption kinetics and thermodynamics. Results show that adsorption fitted to Langmuir model and followed a kinetic model of pseudo-second-order. The adsorption capacity of Pb(II) onto the Ch/Si/P composites membrane is 0.16 mmol/g. The relative selective factor (αf) value of Pb(II)/Rhodamine B is 2.38. This means that Pb(II) can be determined even in the presence of Rhodamine B interference.

Electrolyte membrane is an important component in fuel cell system, because it may influence fuel cell performance. Many efforts have been done to produce electrolyte membrane to replace comercial membrane. In this research, electrolyte membrane is composed of chitosan as an organic matrix and fly ash modified with CTAB and silane as inorganic filler. Fly ash is modified using silane as coupling agent to improve interfacial morphology between organic matrix and inorganic filler. This research aims to determine the best membrane performance based on its characteristics such as water uptake, mechanical properties, proton conductivity, and methanol permeability. The steps that have been done include silica preparation from fly ash, modification of silica surface with CTAB, silica coupling process with silane, synthesis of membranes with inversion phase method, and membrane characterization. The result shows that membrane C-FA/CTAB-Silane 10% (w/w) has the best performance with proton conductivity 8.00 x 10-4 S.cm-1, methanol permeability 3.37 x 10-7 cm.s-1, and selectivity 2.12 x 103 S.s.cm-3. The result of FTIR analysis on membrane C-FA/CTAB-Silane 10% shows that there is only physical interaction occured between chitosan, fly ash and silane, because there is no peak differences significantly at wave number 1000-1250 cm-1, while morphology analysis on membrane with Scanning Electron Microscopy (SEM) shows good dispersion and there is no agglomeration on chitosan matrix.

Adsorption of Crystal Violet (CV) dye using zeolite A synthesized from coal fly ash (ZA) has been done. Effect of pH, contact time, and the initial concentration of dye adsorption was studied in this adsorption. Model experimental of adsorption isotherms and adsorption kinetics were also studied. The adsorption is done in a batch reactor at room temperature. A total of 0.01 g of zeolite A was added to the Erlenmeyer flask 50 mL containing 20 mL of the dye solution of Crystal Violet in a variety of conditions of pH, contact time and initial concentration. Furthermore, Erlenmeyer flask and its contents were shaken using an orbital shaker at a speed of 200 rpm. After a specified period of adsorption, the solution was centrifuged for 2 minutes so that the solids separated from the solution. The concentration of the dye after adsorption determined using Genesis-20 Spectrophotometer. The results showed that the Zeolite A synthesized from coal fly ash could be used as an effective adsorbent for Crystal Violet dye. The optimum adsorption occurs at pH 6, and contact time 45 minutes. At the initial concentration of 2 to 6 mg/L, adsorption is reduced from 79 to 62.8%. Crystal Violet dye adsorption in zeolite A fulfilled kinetic model of pseudo-order 2 and model of Freundlich adsorption isotherm.

Adsorption of Cr(III) and Cr(VI) in aqueous solution by the zeolite A from coal fly ash modified hexadecyltrimethylammonium bromide (HDTMAB) at various pH conditions has been carried out. Zeolite A was synthesized from fly ash through modified alkaline fusion hydrothermal process in a reactor stainless steel. The surface modification was performed using cationic surfactant HDTMAB twice as much as the cationic exchange capacity of the elite A resulted. The surfactant modified zeolite A was then applied to adsorption the metal ion chromium as Cr(III) and Cr(VI) in aqueous solution. The results showed that the acidity (pH) of adsorption conditions, affect the ability of adsorption surfactant modified zeolite A (SMZA) to Cr(III) and Cr(VI) in aqueous solution. The optimum pH conditions for the adsorption of Cr(III) and Cr(VI) on SMZA exist at pH 6. Surfactant modified zeolite A capable to adsorb either cation Cr(III) or anion Cr(VI). Adsorption of SMZA on Cr(III) increased from 36.30% to 97.04% with the increase the acidity of pH of 2 to 6. Adsorption SMZA to Cr(VI) is lower than the adsorption of the Cr3+, adsorption increasing from 19.63 to 64.07% with increase pH of 2 to 6