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HOW TO WRITE INTRODUCTION Yateman Arryanto Jurusan Kimia Fakultas MIPA UGM Yogyakarta.

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Presentasi berjudul: "HOW TO WRITE INTRODUCTION Yateman Arryanto Jurusan Kimia Fakultas MIPA UGM Yogyakarta."— Transcript presentasi:

1 HOW TO WRITE INTRODUCTION Yateman Arryanto Jurusan Kimia Fakultas MIPA UGM Yogyakarta

2 2 Apa yang terpikir pada saat membaca pendahuluan suatu paper ?  Bagaimana Struktur dan format pendahuluan ?  Bagaimana isi dalam pendahuluan ?  Bagaimana alur pikir dalam pendahuluan ?

3 Characterization of silica-coated silver nanoparticles prepared by a reverse micelle and hydrolysis–condensation process Nobuhiro Haguraa,W. Widiyastuti, Ferry Iskandar, Kikuo Okuyamaa, ∗ Chemical Engineering Journal 156 (2010) 200–205 ( at Silver 2010, 21 ) Key word : i.Silica-coated silver, ii.Nano particles, iii.Reverse micelle and hidrolysis-condensation proses

4 4 It is well known that nanoparticles exhibit great properties that differ remarkably from their bulk materials. They are used in many application : microelectronic materials, chemical and mechanical industries, and pharmaceutical and biomaterial production (1). Howewer Silica nanoparticles and silica coated nano particles are both of interest because their surface plasmon resonance (SPR) characterizes both linear and nonlinear optical properties (5,6) It is common to prepare a colloid of meta nanoparticles prior to the silica coating process. Among We used this method to produce silver nanoparticles prior to coating them with silica (6) The preparation of silica-coated silver nanoparticles has been reported by previous investigators and summarized by Liz-Marzan and Mulvaney (2). Geirseg and co-workers reported However, the agglomeration of silver nanoparticles as core material persited when using this method. The use of a non-ionic surfactant such as Igepal CO Therefore, a change in the size of silica might be accurately predicted in this synthesis. For the present study In addition the optical absorbance spectra of silver nanoparticles and silica-coated Were evaluated to characterize their surface plasmon resonance (SPR) INTRODUCTION CHOPPING METHOD SENTENCES TO SENTENCES

5 1.Nano particles exhibit great properties that differ from their bulk materials and they are used in many applications : chemical and mechanical industries, microelectronic materials, and pharmaceutical and biomaterial production [1]. 2.Nanoparticles either in powder or colloid form tend to agglomerate and form larger particles when they are aged over a few days resulting in the degradation of their characteristics. 1. Introduction General Background Specific or Scientific Background Limitation properties of nano particles Need to be coated

6 3.An attempt has been made to maintain un- agglomerated nanoparticles by individually coating the metal nanoparticles called core–shell nanoparticles. 4.The shell also functions to prevent the degradation of characteristic performance caused by the agglomeration process and to control the distance between core particles by adjusting the shell thickness of core–shell particles. 1. Introduction Specific or Scientific Background

7 5.Moreover, core–shell nanoparticles may exhibit unique characteristics and the properties of the core can be altered. 6. As a shell material, silica is preferred because it is easy to control the deposition process, chemical inertness, and optical transparency in the visible range [2–4]. 7.Silver nano particles and silica-coated silver nano particles are both of interest because their Surface Plasmon Resonance (SPR) characterizes both linear and on linear optical properties [5,6]. 1. Introduction Specific or Scientific Background

8 8.Among preparation methods for silver nanoparticles – chemical reduction, photochemical, electrochemical, and biochemical – the microemulsion or micelle method has advantages such as uniform shape and size-controllable particles [7]. 9.The use of oleylamine as both a reducing agent by thermal decomposition and a monolayer protective agent has been reported by previous investigators in the production of mono dispersed functional nanoparticles such as gold, silver and magnetite [8– 10]. 1. Introduction Specific or Scientific Background

9 10.Better control of the size and size distribution of silver nanoparticles, as well as a reduction mechanism for the silver ion, has been reported with use of the oleylamine–liquid paraffin system [11]. 11.This method has promise for the large-scale synthesis of organoamine-protected nanoparticles, because it is inexpensive, versatile, and very reproducible. We used this method to produce silver nanoparticles prior to coating them with silica [6]. Specific or Scientific Background 1. Introduction

10 12.The preparation of silica-coated silver nanoparticles has been reported by previous investigators and summarized by Liz-Marzan and Mulvaney [2] 13.Giersig and co-workers reported a gold and silver colloid being coated with silica using a silane coupling agent, but the silica thickness was only approximately 2–4nm after a 24-h reaction time [3,12]. 14.The Stöber method is a common method used to prepare silica as shells wherein the reaction is a base- catalyzed hydrolysis of tetraethoxysilane (TEOS) followed by condensation to form silica particles [13]. 1. Introduction Specific or Scientific Background

11 15.In the case of silica-coated iron oxide, no pretreatment is required to promote deposition and adhesion of silica because the iron oxide particle surface has a strong affinity toward silica [14]. 16.On the other hand, silver and gold nanoparticles tend to flocculate when the Stöber method is applied directly because of their low affinity for silica. 17.Liz-Marzan and Philipse coated gold nanoparticles with octadecyl chains that dissolved in organic solvent and used Ludox hydrosol as silica seed before they were reacted with TEOS by Stöber synthesis for silica growth [15]. However, most gold nanoparticles are not coated by silica, and agglomerations between silica particles can be observed. 1. Introduction Specific or Scientific Background

12 17.Kobayashi et al. prepared silica-coated silver nanoparticles using borohydride as a reduction agent and silica as a coating material with the modified Stöber method [16]. They used dimethylamine (DMA) to obtain a proper coating of silica onto silver nanoparticles. The shell thickness can be controlled by varying the concentration of TEOS. 18.Another modified Stöber method applied by our group involved the injection of silver nanoparticles into hexadecyltrimethyl ammonium bromide (HTAB) dissolved in de-ionized water before coating by TEOS [6]. Most silver nanoparticles coated by meso porous silica were generated using this method. However, the agglomeration of silver nanoparticles as a core material persisted when using this method 1. Introduction Specific or Scientific Background

13 19.The use of a non-ionic surfactant such as Igepal CO- 520 to obtain moredispersed colloidal nanoparticles has been reported.Areverse microemulsion method that uses Igepal CO-520 as a surfactant has been reported in the synthesis of silica-coated gold and silver nanoparticles using hydrazine hydrate as a reduction agent [17]. 20.This method also has been reported in the synthesis of silica-coated gold nano particles using oleylamine to stabilize the gold nano particles prior to the coating process [18]. 1. Introduction Specific or Scientific Background

14 21.The effect of structure in the formation of silica nano particles using a hydrolysis reaction and condensation of TEOS in nonionic water-in-oil microemulsion was characterized by Chang and Fogler [19]. 22.Three types of nonionic surfactants, including Igepal CO-520 and two types of oils (heptane and cyclohexane), were used for comparison. 23.From the results, the silica reacting species in Igepal CO-520 microemulsion led to the most consumption of TEOS among surfactants. Therefore, a change in the size of silica might be accurately predicted in this synthesis method. Specific or Scientific Background 1. Introduction

15 24.For the present study, we combined methods from several groups based on the advantages offered for control in the preparation of silica-coated silver nanoparticles. We used three consecutive methods to prepare these particles: (i) the preparation of colloidal silver nanoparticles, (ii) a silica-coated silver process, and (iii) the selection of a surfactant as a surface modification during the coating process. FRONT LINE RESEARCH 1. Introduction

16 25.Oleylamine and ascorbic acid were used as a surfactant and a reduction agent, respectively, of silver nitrate in the synthesis of silver nanoparticles. Igepal CO-520 was selected as a surfactant for the synthesis of silica-coated silver nanoparticles during the hydrolysis reaction and condensation of TEOS. The particle morphology and the thickness of the silica shell were controlled by controlling the reaction time and the TEOS concentration FRONT LINE RESEARCH 1. Introduction

17 26.These experimental results were compared to the theoretical approach by applying the rate of the hydrolysis reaction of TEOS to the calculation to predict the thickness of silica coating. In addition, the optical absorbance spectra of silver nano particles and silica-coated silver nano particles, both dispersed in liquid medium and film, were evaluated to characterize their surface plasmon resonance (SPR). FRONT LINE RESEARCH 1. Introduction

18 GENERAL BACKGROUND SCIENTIFIC BACKGROUND FRONT LINE RESEARCH 1 kalimat No : 1 3 kalimat No : 24,25 & kalimat No : 2 s/d 23 STATE OF THE ARTFRONT LINE

19 19 NoFunctionInformation 1General Background  Great Properties and Application of NP 2Scientific Background  Tend to agglomerate  Tend to be degradation their NP properties 3Scientific Background  To prevent the agglomeration of NP need to be coated 4Scientific Background  Shell function, to control shell thickness 5Scientific Background  Core shell exhibit unique character 6Scientific Background  Silica is preferred as shell material 7Scientific Background  Silica coated silver NP has SPR properties 8Scientific Background  The micro emulsion or micelle method for silver NP is easy to control the shape and size 9Scientific Background  The use of oleylamine as reducing and monolayer protective agents  Succes preparation of Gold, Silver and Magnetite NP by using Oleylamine

20 20 NoFunctionInformation 10Scientific Background  The use of oleylamine–liquid paraffin system to control the shape and size of silver NP and reducing mechanism of ion silver 11Scientific Background  The micro emulsion or micelle method has promise for the large-scale synthesis of organoamine-protected nanoparticles (Silver NP) inexpensive, versatile, very reproducible The reason of choosing method of NP Silver preparation

21 21 NoFunctionInformation 12Scientific Background  The preparation of silica-coated silver nanoparticles has been reported by Liz- Marzan and Mulvaney 13Scientific Background  Giersig dkk reported a gold and silver colloid being coated with silica using a silane coupling agent,  The silica thickness was 2–4 nm after 24-h reaction time 14Scientific Background  The Stöber method for preparation of silica as shells base on catalyzed hydrolysis of TEOS followed by condensation to form silica particles 15Scientific Background  For silica-coated iron oxide, no pretreatment is required for coating silica ( iron oxide has a strong affinity for silica ) 16Scientific Background  For silver and gold nanoparticles tend to flocculate when the Stöber method is applied directly ( Silver has a low affinity for silica)

22 22 NoFunctionInformation 17Scientific Background  Silica-coated silver NP using boronhydride as a reduction agent and silica as a coating material with the modified Stöber method [16].  Used dimethylamine (DMA) to obtain a proper coating and controlled the shell thickness by varying the concentration of TEOS. 18Scientific Background  Used of hexadecyltrimethyl ammonium bromide (HTAB) dissolved in de-ionized water before coating by TEOS [6].  The agglomeration of silver nanoparticles as a core material persisted when using this method 19Scientific Background  The use Igepal CO-520 to obtain more dispersed colloidal nanoparticles  Igepal CO-520 as a surfactant has been reported in the synthesis of silica-coated gold and silver nanoparticles using hydrazine hydrate as a reduction agent [17].

23 23 NoFunctionInformation 20Scientific Background  The use of oleylamine to stabilize the gold nano particles prior to the coating process 21Scientific Background  The use of a hydrolysis reaction and condensation of TEOS in nonionic water-in-oil microemulsion for synthesis of silica nano particles 22Scientific Background  The use of nonionic surfactants, Igepal CO- 520 and two types of oils (heptane and cyclohexane) 23Scientific Background  In microemulsion Igepal CO-520 more consumption of TEOS among surfactants.  A change in the size of silica might be accurately predicted in this synthesis method.

24 24 NoFunctionInformation 24Scientific Background  We combined methods from several groups based on the advantages offered for control in the preparation of silica-coated silver nanoparticles.  We used three consecutive methods : (i) the preparation of colloidal silver nanoparticles, (ii) a silica-coated silver process, and (iii) the selection of a surfactant as a surface modification during the coating process. 25Scientific Background  Oleylamine, ascorbic acid and silver nitrate were used in the synthesis of silver nanoparticles.  Igepal CO-520 was selected as a surfactant for the synthesis of silica-coated silver nanoparticles during the hydrolysis reaction and condensation of TEOS.  The particle morphology and the thickness of the silica shell were controlled by controlling the reaction time and the TEOS concentration

25 25 NoFunctionInformation 26Scientific Background  These experimental results were compared to the theoretical approach by applying the rate of the hydrolysis reaction of TEOS to the calculation to predict the thickness of silica coating.  The optical absorbance spectra of silver nano particles and silica-coated silver nano particles, both dispersed in liquid medium and film, were evaluated to characterize their surface plasmon resonance (SPR).

26 GENERAL BACKGROUND SCIENTIFIC BACKGROUND FRONT LINE RESEARCH 1 kalimat No : 1 3 kalimat No : 24,25 & kalimat No : 2 s/d 23 ( Uraian tentang riset yang telah dilakukan peneliti sebelumnya ) STATE OF THE ART ( Uraian tentang riset yang akan dilakukan ) FRONT LINE

27 27 Research PlanScientific Contribution  We combined methods from several groups based on the advantages offered for control in the preparation of silica-coated silver nanoparticles. ( 24 )  Developed new method by combined of : (i) micro emulsion of micelle and (ii) hydrolysis of TEOS  Three consecutive process : (i)The colloidal preparation, (ii) The silica coated process, (iii) The surfactant selection  We used three consecutive methods : (i) the preparation of colloidal silver nanoparticles, (ii) a silica-coated silver process, and (iii) the selection of a surfactant as a surface modification during the coating process. ( 24 )

28 28 Research PlanScientific Contribution  Oleylamine, ascorbic acid and silver nitrate were used in the synthesis of silver nanoparticles. (25)  Developed new method by combined of : (i) micro emulsion of micelle and (ii) hydrolysis of TEOS  Three consecutive process : (i)The colloidal preparation, (ii) The silica coated process, (iii) The surfactant selection  Igepal CO-520 was used as surfactant  Controlling reaction time and the TEOS concentration to control morphology and the thickness  Igepal CO-520 was selected as a surfactant for the synthesis of silica-coated silver nanoparticles during the hydrolysis reaction and condensation of TEOS. ( 25 )  The particle morphology and the thickness of the silica shell were controlled by controlling the reaction time and the TEOS concentration ( 25 )

29 29 Research PlanScientific Contribution  To compare the experimental results to the theoretical approach of the rate of the hydrolysis reaction of TEOS to thickness of silica coating  Developed new method by combined of : (i) micro emulsion of micelle and (ii) hydrolysis of TEOS  Three consecutive process : (i)The colloidal preparation, (ii) The silica coated process, (iii) The surfactant selection  Igepal CO-520 was used as surfactant  Controlling reaction time and the TEOS concentration to control morphology and the thickness  The experimental and theoritical result of the relation between hydrolysis rate and the thickness  The optical absorben spectra of silver and coated silica silver NP  To measure of the optical absorbance spectra of (i) silver nano particles and (ii) silica-coated silver nano particles (in liquid medium and film) (SPR characterization)

30 30 3 kalimat No : 24,25 & 26 ( Uraian tentang riset yang akan dilakukan ) FRONT LINE NEW SCIENTIFIC CONTRIBUTION  Developed new method by combined of : (i) micro emulsion of micelle and (ii) hydrolysis of TEOS  Three consecutive process : (i)The colloidal preparation, (ii) The silica coated process, (iii) The surfactant selection  Igepal CO-520 was used as surfactant  Controlling reaction time and the TEOS concentration to control morphology and the thickness of coated silica  The experimental and theoritical result of the relation between hydrolysis rate and the thickness  The result of optical absorben spectra of silver NP and coated silica silver NP

31 GENERAL BACKGROUND SCIENTIFIC BACKGROUND FRONT LINE RESEARCH 1 kalimat No : 1 3 kalimat No : 24,25 & kalimat No : 2 s/d 23 ( Uraian tentang riset yang telah dilakukan peneliti sebelumnya ) STATE OF THE ART ( Uraian tentang riset yang akan dilakukan ) FRONT LINE

32 GENERAL BACKGROUND

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35 PEMANFAATAN BULU Anas platyrhynchos sp SEBAGAI ADSORBENT ION LOGAM BERAT PADA LIMBAH INDUSTRI Dewasa ini, banyak sekali industrI yang berkembang di sekitar kita baik itu industri tekstil, kebutuhan rumah tangga bahkan hingga industri makanan. Berkembangnya industrI ini, tentunya memberikan manfaat positif karena dapat mengurangi jumlah pengangguran di Indonesia. Namun, nyatanya adanya industri-industri ini juga menimbulkan masalah baru yaitu berkaitan dengan limbah yang dihasilkan. Seperti yang kita ketahui, tidak semua limbah dari industri aman untuk dibuang langsung ke lingkungan. Misalnya saja limbah logam Cu, Ni, Pb, Cd dan zat warna dari industri tekstil, atau limbah logam Ni dan Cd dari industri baterai. Oleh karena itu, limbah ini perlu diberi perlakuan khusus terlebih dahulu sehingga aman untuk dilepas ke lingkungan dan tidak mencemari lingkungan. BAB I PENDAHULUAN 1.1.Latar Belakang GENERAL BACKGROUND

36 Salah satu metode yang cukup efektif untuk mengubah limbah menjadi aman adalah dengan adsorpsi. Untuk itu, diperlukan adsorben khusus yang bersesuaian dengan limbah yang ingin diadsorb. Namun sayangnya, harga adsorben tidaklah murah apalagi untuk ukuran jumlah limbah yang cukup banyak. Untuk meningkatkan nilai ekonomis maka kita dapat membuat sendiri adsorben yang kita inginkan. Salah satu bahan yang cukup murah dan mudah didapat untuk dijadikan adsorben adalah keratin. Keratin sendiri merupakan zat yang banyak terkandung di rambut, bulu atau kuku. Oleh karena itu, pada penelitian ini digunakan bulu unggas bebek, dikarenakan mengandung keratin yang cukup banyak. Tak hanya itu, bahan dasar ini juga mudah didapat dan relatif murah. Bulu bebek bisa didapat dari peternakan atau pemotongan bebek, dimana biasanya bulunya tidak digunakan. Alhasil, selain murah penelitian ini juga memanfaatkan dan mendaya gunakan bahan yang sebelumnya tidak memiliki manfaat khusus menjadi lebih bermanfaat bagi lingkungan. GENERAL BACKGROUND

37 Pada penelitian ini akan dilakukan pengujian kemampuan keratin pada bulu bebek untuk mengadsorp ion logam pada limbah sehingga limbah lebih aman saat dilepas di lingkungan. Untuk meningkatkan kemampuan adsorbsi, maka adsorben akan ditambah atau diaktivasi dengan asam askorbat sehingga dapat pula digunakan untuk membandingkan pengaruh asam askorbat itu sendiri terhadap kemampuan adsorbsi. Selanjutnya, untuk dilakukan analisis dengan menggunakan spectrometer uv vis dan AAS untuk membandingkan limbah sebelum dan sesudah adsorbsi. Tak hanya itu, diberikan beberapa variable perlakuan khusus untuk menentukan pengruhnya terhadap adsorbs, seperti temperature, lama waktu kontak atau adsorpsi serta konsentrasi logam dalam limbah. GENERAL BACKGROUND

38 SITOTOKSISITAS EKSTRAK BAWANG DAYAK (Eleutherine palmifolia) TERHADAP SEL KANKER SERVIKS BAB I PENDAHULUAN 1.1.Latar Belakang Pada zaman ini dimana segala aktivitas dituntut serba cepat, masyarakat cenderung tidak memperhatikan pola hidup sehat dan cenderung memilih segala bahan yang instan.Tentu saja hal ini dapat memicu berbagai masalah kesehatan. Sehingga dewasa ini banyak sekali bermunculan penyakit- penyakit kronik seperti kanker,stroke,diabetes dan penyakit kronis lainnya. Kalimat yang tidak penting

39 Kanker merupakan penyakit dengan karakteristik adanya gangguan atau kegagalan mekanisme pengaturan multiplikasi pada organisme multiseluler sehingga terjadi perubahan perilaku sel yang tidak terkontrol. Perubahan tersebut disebabkan adanya perubahan atau transformasi genetik, terutama pada gen-gen yang mengatur pertumbuhan, yaitu protoonkogen dan gen penekan tumor. Sel-sel yang mengalami transformasi terus-menerus berproliferasi dan menekan pertumbuhan sel normal. Kanker merupakan salah satu penyakit dengan angka kematian yang tinggi. Data Global action against cancer (2005) dari WHO (World Health Organization) menyatakan bahwa kematian akibat kanker dapat mencapai angka 45% dari tahun 2007 hingga 2030, yaitu sekitar 7,9 juta jiwa menjadi 11,5 juta jiwa kematian. Di Indonesia, menurut laporan Riskesdes (2007) prevalensi kanker mencapai 4,3 per 1000 penduduk dan menjadi penyebab kematian nomor tujuh (5,7%) setelah sroke, tuberkulosis, hipertensi, trauma, perinatal dan diabetes melitus. Penulisan general background terlalu banyak

40 Salah satu jenis kanker adalah kanker leher rahim atau kanker serviks,kanker jenis ini adalah tumor ganas primer yang berasal dari metaplasia epitel di daerah skuamokolumner junction yaitu daerah peralihan mukosa vagina dan mukosa kanalis servikalis. Kanker serviks merupakan kanker yang terjadi pada serviks atau leher rahim, suatu daerah pada organ reproduksi wanita yang merupakan pintu masuk ke arah rahim, letaknya antara rahim (uterus) dan liang senggama atau vagina. Kanker leher rahim biasanya menyerang wanita berusia tahun.(Hacker,2000). Kanker serviks di Indonesia merupakan kanker terganas kedua setelah kanker payudara dan diperkirakan diderita wanita setiap tahunnya. Di Indonesia kanker serviks menempati posisi teratas dari semua jenis kanker yang ada dengan kurang lebih 68% dari total penderita kanker dengan prevalensi 28,66%. Penulisan general background terlalu banyak

41 Penyakit kanker biasa ditangani dengan cara kemoterapi dan juga dengan operasi. Cara pengobatan seperti ini memiliki beberapa kelemahan seperti biaya nya yang sangat mahal dan juga menimbulakn berbagai macam efek samping. Maka dari itu penulis ingin meneliti tentang kemungkinan senyawa bakal obat baru yang akan diambil dari ekstrak bawang dayak atau bawang tiwai yang selama ini dianggap dapat menyembuhkan berbagai penyakit dan salah satu contohnya adalah kanker. Bawang dayak merupakan tumbuhan khas Kalimantan Tengah. Tumbuhan ini secara turun temurun telah dipergunakan oleh masyarakat Dayak sebagai tumbuhan obat untuk berbagai jenis penyakit seperti kanker payudara dan kolon, hipertensi, diabetes mellitus, hiperkolesterol dan stroke. Penggunaan bawang sabrang dapat digunakan dalam bentuk segar, simplisia, manisan dan dalam bentuk bubuk (powder) (Galingging, 2009). Hasil penelitian menunjukan bahwa umbi lapis bawang dayak mengandung senyawa naftakuinon dan turunannya seperti elecanacine, eleutherine, eleutherol dan eleuthernone (Hara, et al., 1997). Alves et al. (2003) telah meneliti naftakuinon dari salah satu varian bawang dayak yaitu Eleutherine bulbosa yang memiliki aktivitas biologis sebagai antimikroba, antiviral, antiinflamasi, antipiretik, anti jamur, efek antiproliferatif dan sitotoksik terhadap kanker kolon dan kanker serviks GENERAL BACKGROUND Penulisan general background terlalu banyak

42 IMOBILISASI ASAM HUMAT PADA BEADS KITOSAN DENGAN METODE PENGIKATAN-SILANG DAN APLIKASINYA SEBAGAI ADSORBEN Hg(II) BAB I PENDAHULUAN 1.1.Latar Belakang Logam berat adalah unsur-unsur yang memiliki berat atom antara 63.5 dan serta memiliki berat jenis lebih dari 5.0. Dengan tingginya perkembangan industri seperti fasilitas pelapisan logam, operasi pertambangan, industri pupuk, baterai, industri kertas dan pestisida dan lain sebagainya, kandungan logam berat dalam air limbah yang dilepaskan dalam perairan bebas secara langsung maupun tidak langsung menjadi meningkat, terutama dalam negara-negara berkembang. Tidak seperti kontaminan organik, logam berat merupakan kontaminan yang tidak biodegradable serta cenderung terakumulasi kedalam organisme hidup. Pada umumnya ion logam berat beracun dan karsinogenik (Fenglian dan Wang, 2011). General background

43 Upaya untuk mengatasi berbagai pencemaran logam berat adalah dengan cara menurunkan konsentrasi pencemar hingga dibawah ambang batas baku mutu sebelum dibuang ke lingkungan. Metode yang umum digunakan adalah metode reduksi, pertukaran ion, osmosis balik, koagulasi, adsorpsi atau kombinasi dari beberapa metode tersebut (Santoso, 2008). Saat ini metode adsorpsi telah diakui sebagai metode yang efektif dan ekonomis sebagai pengolahan air limbah yang mengandung logam berat. Proses adsorpsi menawarkan fleksibilitas dalam desain dan operasi serta dalam banyak kasus dapat meningkatkan kualitas effluent (Fenglian dan Wang, 2011). Melalui metode adsorpsi dapat digunakan adsorben yang mudah didapatkan atau diisolasi seperti zeolit, lempung, asam humat, resin polimerik dan kitosan (Santoso, 2008). General Scientific background

44 Salah satu bahan alam indonesia yang sangat potensial untuk dijadikan adsorben adalah asam humat yang berasal dari tanah gambut. Asam Humat telah diteliti dan terbukti memiliki kapasitas adsorpsi yang tinggi terhadap logam berat seperti Pb(II), Cd(II) dan Cr(III) (Santoso, 2008). Walau demikian, sifat asam humat yang mudah larut pada pH medium netral dan basa menjadi perhatian para peneliti. Untuk mengatasi permasalahan stabilitas asam humat, beberapa peneliti telah mencoba melakukan kajian imobilisasi asam humat pada berbagai substrat atau supporting material seperti aminopropil, kitin, kitosan dan silika. Meskipun proses immobilisasi berhasil meningkatkan kestabilan asam humat, kapasitas adsorpsinya relatif tidak berubah dan justru mengalami penurunan diakibatkan tertutupnya situs aktif dari asam humat setelah proses imobilisasi. General Scientific background

45 Sehubungan dengan adanya hambatan transfer massa, biasanya adsorben dibuat dalam bentuk partikel-partikel yang sangat kecil untuk meningkatkan luas permukaannya. Namun demikian, partikel-partikel berukuran kecil telah terbukti tidak sesuai untuk sistem kolom karena dapat mengakibatkan column clogging dan hambatan hidrodinamis. Kitosan dalam bentuk gel beads merupakan suatu upaya alternatif karena dalam bentuk ini dapat terjadi perbaikan sifat difusi dan hidrodinamis (Gibal, 2004). Oleh karenanya pengikatan-silang terproteksi asam humat pada kitosan gel beads dalam rangka meningkatkan kapasitas adsorpsinya menarik untuk dilakukan. Pada Penelitian ini dikaji proses imobilisasi asam humat pada kitosan dalam bentuk beads untuk kemudian diterapkan menjadi adsorben ion logam Hg(II). Proses imobilisasi dalam bentuk beads diharapkan dapat meningkatkan stabilitas dan juga kapasitas adsorpsi dari asam humat terhadap ion Hg(II). Penelitian ini diharapkan dapat dijadikan sebagai suatu kajian atau referensi didalam teknik stabilisasi asam humat menggunakan polimer alami yang murah dan mudah didapatkan. Selain itu juga dapat memberikan alternatif metode yang murah dan ramah lingkungan untuk mengadsorp logam Hg(II). General Scientific background No state of the art

46 Be best Lecture and good luck


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