24 research outputs found

    UPAYA PEMANFAATAN LIMBAH KULIT RAJUNGAN (Portunus pelagicus) SEBAGAI MEMBRAN KITOSAN CROSSLINKED FORMALDEHID

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    Telah dilakukan penelitian dalam upaya pemanfaatan limbah kulit rajungan sebagai membran kitosan crosslinked formaldehid. Isolasi kitin dilakukan dengan proses deproteinasi, demineralisasi, depigmentasi. Transformasi kitin menjadi kitosan dilakukan dengan proses deasetilasi. Penentuan derajat deasetilasi dilakukan dengan FTIR. Dipelajari hubungan konsentrasi NaOH, temperatur dan lama proses terhadap derajat deasetilasi. Sintesis membran dilakukan dengan teknik inversi fasa. Crosslinked dilakukan terhadap membran kitosan untuk mendapatkan ukuran pori yang lebih kecil. Diperoleh hasil bahwa peningkatan derajat deasetilasi dapat meningkatan sifat mekanik membran. Besarnya derajat deasetilasi sendiri dipengaruhi faktor¬-faktor yaitu: konsentrasi NaOH, suhu dan lama proses. Derajat deasetilasi tertinggi diperoleh 72,28% pada konsentrasi NaOH 40%, suhu 80°C dan waktu 5 jam. Cross/inked formaldehid meningkatkan tensile strength dari 27,06 MPa menjadi 69,6 MPa, juga ukuran pori menjadi lebih kecil seperti ditunjukkan dari hasil SEM. Rejeksi COD tertinggi 83,95% pada komposisi membran 3,5 gr kitosan, pelarut 80 ml, suhu pengeringan 80°C dan fluks 59,66 Lm-2. Rejeksi terhadap kekeruhan 47,95% Berdasarkan data-data tersebut maka membran kitosan cross/inked formaldehid memenuhi syarat untuk digunakan sebagai membran mikrofiltrasi

    PENGEMBANGAN ADSORBEN LIMBAH TAHU PADAT (LTP) TERIMMOBILISASI PADA PERMUKAAN SILIKA UNTUK PENYISIHAN BERBAGAI ION LOGAM BERAT BIVALENSI DARI SAMPEL LIMBAH SINTETIK

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    Penelitian ini dilakukan dengan tujuan untuk mengembangkan adsorben potensial khususnya berbasis biomassa yaitu limbah tahu padat (LTP) yang diimmobilisasikan pada permukaan silika untuk penyisihan tiga jenis ion logam berat yakni ion Pb2+, Cd2+, dan Ni2+. Selanjutnya dilakukan karakterisasi adsorben LTP- Silika yang meliputi: uji populasi bakteri baik untuk limbah tahu padat maupun limbah tahu padat terimmobilisasi silika, penentuan harga pH zero charge potential (pH pcz) dari adsorben yaitu sebesar 8,40, mempelajari pengaruh pH terhadap adsorpsi ion Pb2+, ion Cd2+, ion Ni2+ yang diperoleh harga pH optimum sebesar 6, uji derajat kristalinitas dengan XRD, karakterisasi jenis interaksi ikatan antara LTP dan Silika menggunakan FTIR, karakterisasi dengan SEM-EDX untuk mengetahui topografi permukaan serta kandungan unsur dari adsorben LTP-silika. Penentuan ukuran partikel adsorben yang dianalisis dengan zetasizer nano particles, karakterisasi luas area permukaan total, ukuran pori dan volume pori dari adsorben LTP-silika dengan metode BET-BJH. Sedangkan untuk studi model adsorpsi isotermis yang cocok untuk ketiga ion logam berat tersebut adalah model BiLangmuir dan jenis adsorpsinya adalah adsorpsi fisik dengan harga energi adsorpsi untuk ion Pb2+, Cd2+, dan Ni2+ bertutut-turut adalah 559,02 j.mol-1, 1589,07 j.mol-1, dan 2380,95 j.mol-1 pada 27OC. Studi kinetika adsorpsi untuk ketiga ion logm berat tersebut pada rentang konsentrasi 5-50 ppm pada 27oC untuk Pb2+ memiliki orde satu semu dan dua semu, untuk Cd2+ dan Ni2+ memiliki orde dua semu dengan laju awal adsorpsi sebagai berikut : (h) = Ni2+ > Cd2+ > Pb2+. Studi termodinamika adsorpsi pada rentang suhu 30-60oC pada rentang konsentrasi yang sama untuk ketiga ion logam memiliki harga entalpi adsorpsi rata-rata endotermik sebagai berikut: ΔHads rata-rata : Pb2+ = 95,553 Kj.mol-1, Cd2+ = 122,249 Kj.mol-1 , dan Ni2+ = 111,092 Kj.mol-1. Sedangkan untuk kompetisi didapatkan persentase penyisihan baik dalam campuran Biner dan Terner untuk ketiga jenis ion logam, yaitu: Pb2+, Cd2+, dan Ni2+, ion Pb2+ memiliki persentase penyisihan paling besar

    Studi mekanisme kinetika reaksi pertukaran ion FeIII antara dua jenis ligan siderophore bakteri desferriferrioxamine B dan azoverdine dengan ligan EDTA

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    The kinetics of iron exchange and iron removal from two siderophore complex with use of ethylenediaminetetraacetic acid (EDTA) have been examined, using UV-Vis spectrophotometric method. Iron exchange between the ferric complexes of desferriferrioxamine B (siderophore produced by microorganism Azomonas macrocy-togenes) with EDTA was extremely slow under conditions at pH 7.4 and 25oC. Furthermore, pH dependence studies demonstrated that the exchange rate was accelerated as a function of increasing hydrogen ion concentration. Kinetics of iron removal from ferrioxamine B and the ferric complexe of azoverdine with excess of EDTA, show firt-order dependence on the concentration of the iron complex and hydrogen ion at 25oC with first-order rate constant of the dissociation od a ternary complex formed of (16 ±0.4) x 10-3s-1and (1.3 ±0.2) x 10-2s-1 respectivy at pH region between 3.67 and 5.23. variation of pseudo first order rate constant kobswith hydrogen ion concentration shows a saturation kinetics at high constant ligand EDTA concentration (3.0 x 10-2 M) and at low pH region (3.67). the result were interpreted in terms of three-step mechanism, involving : (1) protonation of the ferrioxamine B comples and the ferric comples of azoverdine and (2) subsequent biomolecular reaction with EDTA

    Affordable dye sensitizer by waste

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    Abstract The development of dye sensitizer is growing in line with the increasing demand for renewable energy. A research to obtain a dye sensitizer that is economical, safe, and produces a great value of DSSC efficiency is a challenge unresolved. On the other hand, the efforts for waste reduction are also intensively conducted to create better environment. In this paper, the variation of synthetic dye wastes from batik industries have been successfully applied as dye sensitizer and fabricated on DSSC cells. Congo red (1.0133%) yielded higher efficiency than rhodamine B (0.0126%), methyl orange (0.7560%), and naphthol blue black (0.0083%). The divergence of the efficiency of DSSC is very dependent upon the chromophore group owned by dye. This study has proven that the more chromophore group possessed by dye, the higher the efficiency of DSSC generated. This research concludes that the dye wastes have a bright future to be implemented as dye sensitizer on solar cells

    RETRACTED: Novel drug delivery carrier from alginate-carrageenan and glycerol as plasticizer

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    This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).This article has been retracted at the request of the Editors-in-Chief.After a thorough investigation, the Editors have concluded that the acceptance of this article was based upon the positive advice of at least three illegitimate reviewer reports. The reports were submitted from email accounts which were provided to the journal as suggested reviewers during the submission of the article. Although purportedly real reviewer accounts, the Editors have concluded that these were not of appropriate, independent reviewers.This manipulation of the peer-review process represents a clear violation of the fundamentals of peer review, our publishing policies, and publishing ethics standards. Apologies are offered to the reviewers whose identities were assumed and to the readers of the journal that this deception was not detected during the submission process

    Characterization, isotherm, and thermodynamic data for selective adsorption of Cr(VI) from aqueous solution by Indonesia (Ende-Flores) natural zeolite Cr(VI)-imprinted-poly(4-VP-co-EGDMA)-ANZ (IIP-ANZ)

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    In this paper, we report for the first time modification of Indonesia (Ende-Flores) natural zeolite Cr(VI)-imprinted-poly(4-VP-co-EGDMA)-ANZ (IIP-ANZ) as a selective adsorbent for Cr(VI) from aqueous solution. The IIP-ANZ was synthesized from Cr(VI) as a template, 4-vinylphiridine (4-VP) as complex agent and as functional monomer, ethylene glycol dimethyl acrylate (EGDMA) as a cross-linker agent, benzoyl peroxide (BPO) as initiator and ethanol/acetone as a porogen. The optimization adsorption parameters optimization such as adsorbent amount, initial pH of sample solution, contact time and temperature were studied. The maximum adsorption capacity was 4.210 mg/g adsorbent. The adsorption process follow Freundlich isotherm model. Under the competitive condition, the adsorption capacity of IIP-ANZ for Cr(VI) is higher than Pb(II), Mn(II), NI(II) and Cr(III). Moreover, the reusability of the IIP-ANZ particle was tested for five times and no significant loss in adsorption capacity observed. Keywords: Natural zeolite, Imprinted-polymer, Selective adsorption, Hexavalent chromiu

    Characterization, kinetic, and isotherm data for Cr(VI) removal from aqueous solution by Cr(VI)-imprinted poly(4-VP-co-MMA) supported on activated Indonesia (Ende-Flores) natural zeolite structure

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    The adsorption performance of Cr(VI) on the Cr(VI)-imprinted poly(4-VP-co-MMA) (IIP) supported on Activated Indonesia (Ende-Flores) natural zeolite (ANZ) structure for Cr(VI) removal from aqueous solution have been studied. Cr(VI)-imprinted-poly(4-VP-co-MMA)-ANZ (IIP-ANZ) was synthesized using Cr(VI) as a template, 4-vinylphiridine (4-VP) as a complex agent, methyl methacrylate (MMA) as a monomer agent, ethylene glycol dimethylacrylate (EGDMA) as cross-linker and benzoyl peroxide (BPO) as an initiator. XRD, FTIR, SEM-EDX and BET was performed to characterize the synthesized materials. The maximum adsorption capacity was 2.431 mg/g adsorbent at pH 2, contact time of 30 min, under 303 K respectively. Five kinetic and four isotherm models were used to find out the reaction rate of Cr(VI) adsorption processes on this adsorbent. Under the competitive condition, the adsorption capacity of this adsorbent for Cr(VI) is greater than Cr(III), Mn(II) or Ni(II) ions but it less selective if present of Pb(II) ion. Moreover, the reusability of the IIP-ANZ was tested for five times and no significant loss in adsorption capacity observed. Keywords: Activated natural zeolite, Poly(4-VP-co-MMA), Cr(VI) adsorptio

    Utilization of Nanochitosan as Adsorbent of Mercury (Hg) in Gold Ore Processing Waste

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    Mercury pollution in gold ore processing wastewater can cause environmental and health problems. A large amount of mercury pollution causes neurological disease, paralysis, loss of sense of taste, irregular speech, and death. One effective method to reduce mercury amount in the environment is adsorption. Adsorption performance is affected by several factors such as surface area of material, deacetylation degree (DD), and adsorption condition, which is indicated by contact time and mercury concentration. Nanochitosan is used in this research. Effect of deacetylation degree (85%; 87%; 95%), contact time (30;60;90;120 minutes), and variation of mercury concentration (5;10;15;20;25;30 ppm) on adsorption performance was investigated in this research. Nanochitosan in this research is characterized by FTIR, SEM-EDX, BET-BJH, and pH PZC. AAS measures adsorption performance in this research. The result shows that nanochitosan, which has the best adsorption performance, is nanochitosan with a deacetylation degree of 95%, at a contact time of 60 minutes, and mercury concentration is 15 ppm
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