Aku mencintainya karena mencintaiMU

Mungkin kita harus diterpa beribu-ribu masalah dalam hidup. Mulai dari masalah cinta yang menderita remaja sampai keuangan yang mendera keluarga. Tapi yang terpenting, pahamilah bahwa sesungguhnya engkau dicintaiNYA.

Agak sulit memang, ketika kita mencintai seseorang, dia tidak pernah memberikan sinyalemen meng-iyakan kepada kita, terlebih kita tahu bahwa dia orang baik dan ingin memiliki keinginan mulia untuk menikahinya. Tapi ketahuilah, mungkin dia ingin menyimpan perasaan yang sama atau bahkan menunggu seseorang yang lain sehingga tidak pernah mengatakan apapun untuk tidak menyakitimu.

Agak sulit memang, ketika kita memberikan perhatian kepada seseorang dia tidak membalas. Tapi ketahuilah, mungkin itu dia merasa itu adalah sesuatu yang lebih dibanding membalas, yaitu men doakan.

Agak sulit memang, ketika kita ingin menunggu seseorang, jawaban tidak pernah kunjung datang. Tapi ketahuilah, dia pasti meyakinkan dirinya untuk bilang Ya atau Tidak.

Agak sulit memang, ketika kita merasa berpasrah, DIA tidak segera memberikan jawaban atas kepasrahan kita. Tapi ketahuilah, DIA menginginkanmu menjadi lebih dewasa, bersyukur dan ingin engkau menemukan jalanmu sendiri.

Agak sulit memang, ketika kita ingin beribadah dengan baok, cobaan yang mendera bertambah banyak dan telak. Tapi ketahuilah, DIA ingin mengujimu untuk mendapati engkau termasuk orang yang hebat.

Saya mengalami, saya belajar, saya memahami skenario ini, dan saya mencintainya karena mencintaiMU.

karbohidrat...

apa yang musti dibahas yakz...?
kapan-kapan aja deh..
hehehe

Caffeine....

Caffeine is a bitter substance found in coffee, tea, soft drinks, chocolate, some nuts and certain medicines. It has many effects on the body's metabolism, including stimulating the central nervous system. This can make you more alert and give you a boost of energy.
For most people, the amount of caffeine in two to four cups of coffee a day is not harmful. However, too much caffeine can make you restless, anxious and irritable. It may also keep you from sleepingwell and cause headaches, abnormal heart rhythms or other problems. If you stop using caffeine, you could get withdrawal symptoms.
Caffeine is a drug that is naturally produced in the leaves and seeds of many plants. It's also produced artificially and added to certain foods. Caffeine is defined as a drug because it stimulates the central nervous system, causing increased alertness. Caffeine gives most people a temporary energy boost and elevates mood.
Caffeine is in tea, coffee, chocolate, many soft drinks, and pain relievers and other over-the-counter medications. In its natural form, caffeine tastes very bitter. But most caffeinated drinks have gone through enough processing to camouflage the bitter taste.
Teens usually get most of their caffeine from soft drinks and energy drinks. (In addition to caffeine, these also can have added sugar and artificial flavors.) Caffeine is not stored in the body, but you may feel its effects for up to 6 hours.

Caffeine sensitivity (the amount of caffeine that will produce an effect in someone) varies from person to person. On average, the smaller the person, the less caffeine needed to produce side effects. Caffeine sensitivity is most affected by the amount of caffeine a person has daily. People who regularly take in a lot of caffeine soon develop less sensitivity to it. This means they may need more caffeine to achieve the same effects.
Caffeine is a diuretic, meaning it causes a person to urinate (pee) more. It's not clear whether this causes dehydration or not. To be safe, it's probably a good idea to stay away from too much caffeine in hot weather, during long workouts, or in other situations where you might sweat a lot.
Caffeine may also cause the body to lose calcium, and that can lead to bone loss over time. Drinking caffeine-containing soft drinks and coffee instead of milk can have an even greater impact on bone density and the risk of developing osteoporosis.
Caffeine can aggravate certain heart problems. It may also interact with some medications or supplements. If you are stressed or anxious, caffeine can make these feelings worse. Although caffeine is sometimes used to treat migraine headaches, it can make headaches worse for some people.

In the Coca Cola, have 34 mg caffeine. Diet Coke 45 mg, Pepsi 38 mg, 7 up 0 mg (wow), milk chocolate 6 mg, ice tea 70 mg (ummmmzzzz....)



(for the variety source)

Zeolite

like silica gel, zeolite can be used to adsorb the adsorbat, like chemical, water, metals ion or else. this picture shown zeolite A

There is about global warming..

Who's the man don'T know about global warming? There is something funny. But,may be some people like this. They know global warming makes 'water high's position of the earth is different to be highly and dangerous'
The chemists,make it different define than others,like above or some people who's say that't global warming caused from carbon dioxide? How about the statement of chemists?
See you later in the next session.

There is about global warming..

Who's the man don'T know about global warming? There is something funny. But,may be some people like this. They know global warming makes 'water high's position of the earth is different to be highly and dangerous'
The chemists,make it different define than others,like above or some people who's say that't global warming caused from carbon dioxide? How about the statement of chemists?
See you later in the next session.

Sodium 2-Mercaptobenzothiazole

What's Sodium 2-merchaptobenzothiazole...?
let's see..
Sodium 2-Mercaptobenzothiazole is used as an accelerator in the processing of rubber products. There are a number of reports indicating contact dermatitis associated with 2-mercapto- benzothiazole in humans following exposure to rubber (e.g., Correcher and Perez, Contact Derm. 7:275, 1981; Tosti et al., Contact Derm. 13:339, 1985; and Foussereau et al., Contact Derm. 14:233, 1986) as well as in animal models (e.g., Goodwin et al., Contact Derm. 7:248, 1981).
Initial name of this chemical's MBT. And, the same name of this reagent are:

• 2(3H)-BENZOTHIAZOLETHIONE, SODIUM SALT
• 2-(3H)-BENZOTHIAZOLETHIONE, SODIUM SALT
• 2-BENZOTHIAZOLETHIOL, SODIUM DERIV.
• 2-BENZOTHIAZOLETHIOL SODIUM SALT
• 2-BENZOTHIAZOLETHIOL, SODIUM SALT
• 2-MERCAPTO-BENZOTHIAZOLE, SODIUM
• 2-MERCAPTO-BENZOTHIAZOLE, SODIUM DERIV.
• 2-MERCAPTOBENZOTHIAZOLE SODIUM SALT
• 2-MERCAPTOBENZOTHIAZOLE, SODIUM SALT
• BENZOTHIAZOLE, 2-MERCAPTO-, SODIUM DERIV.
• DUODEX
• MERCAPTOBENZOTHIAZOLE SODIUM SALT
• NACAP
• SODIUM, (2-BENZOTHIAZOLYLTHIO)-
• SODIUM 2-BENZOTHIAZOLETHIOATE
• SODIUM 2-BENZOTHIAZOLETHIOLATE
• SODIUM 2-MERCAPTOBENZOTHIAZOLATE
• SODIUM 2-MERCAPTOBENZOTHIAZOLE
• VANCIDE 51

physical characteristic of 2-merchaptobenzothiazole..
Molecular formula : CC7H5NS2Na

Flash Point: >200 ° F (NTP, 1992)

Melting Point: 21.0 ° F (NTP, 1992)

Vapor Pressure: 24.0 mm Hg at 77.0 ° F (NTP, 1992)

Specific Gravity: 1.25-1.28 at 77.0 ° F (NTP, 1992)

Boiling Point: 217.0 ° F at 760 mm Hg (NTP, 1992)

Molecular Weight: 189.23 (NTP, 1992)

Water Solubility: greater than or equal to 100 mg/mL at 68° F (NTP, 1992)

the spectra of 2-merchaptobenzothiazole can see the figure (1)

figure (1) spectra MBT

chamio chemical; national toxicology prog, USA government

Oxygen is Toxic...

U-M scientist says oxygen is toxic to stem cells. Too much O2 turns muscle cells into fat

ANN ARBOR, Mich. oxygen may be good for you, but it's not so great for your stem cells -- according to a new study by scientists at the University of Michigan Medical School. Too much oxygen can kill stem cells, slow growth and even trigger an alternate developmental pathway that converts pre-muscle stem cells into fat cells.

The U-M study, published in the November 2001 issue of the Journal of Cellular Physiology, shows that gene expression patterns change significantly when stem cells are exposed to varying amounts of oxygen, and that these changes alter the basic biologic function of stem cells. In addition to its scientific importance, the U-M study could have important clinical implications for treatment of obesity and diabetes.

"The more primitive the stem cell, the more sensitive it is to oxygen," says Marie Csete, M.D., Ph.D., an assistant professor of cell and developmental biology and an associate professor of anesthesiology in the U-M Medical School, who directed the study.

"We found that skeletal muscle satellite cells grew faster, lived longer and developed into muscle cells more consistently when cultured with the amount of oxygen found in their natural environment." In their natural environment in the body, stem cells never are exposed to the amount of oxygen they encounter in the typical biomedical laboratory.

Csete and colleagues compared growth rates and developmental patterns of stem cell lines and skeletal muscle satellite cells grown in a laboratory atmosphere of 20 percent oxygen to cells grown with the 2 percent to 6 percent oxygen levels found inside the body. Csete grows stem cell cultures in a custom-designed facility, which she can adjust to create an atmosphere with specific amounts of oxygen and other gases.

"The big surprise was that satellite cells isolated from muscle fiber

http://news.bio-medicine.org

Toxicology of Minerals

Many minerals an essential part of a healthy diet. Other minerals are toxic even in tiny amounts, leading nerve dysfunction and memory loss, a weakened immune system, and even kidney damage.

Heavy metals are real trace elements found in industrial wastes, fillings in your teeth, fish and sea products, and in the paint of most houses and buildings — and they can cause you serious harm.

• Alumunium: Found in underarm deodorants, cookware, and foil, aluminum occurs in the earth and naturally in foods, but excessive amounts can be a problem. Heating acidic foods, such as tomato sauces, in aluminum cookware or foil can allow high amounts of aluminum to get into your food.

  Aluminum is also an ingredient in antacids, baking powders, and salt. The best way to prevent aluminum toxicity is to avoid regular exposure to aluminum-containing products, such as antiperspirants, antacids, and cooking in aluminum foil and cookware.

  Linked to Alzheimer’s disease and other senile dementia, aluminum deposits have been found in the brains of people suffering from these mental disorders. Natural aluminum, in the 40–50 mg you may ingest daily in food, may not be a culprit. T

  The aluminum additives in salt and baking powders, and through the skin from deodorants, may lodge in body tissues and potentially cause some problems in the brain and with certain enzymes.

  Toxicity may cause skin rashes, intestinal upset, and harm to the bones and kidneys.

• Arsenic : You may be exposed to arsenic through ocean food, weed killers, and insecticides. Arsenic is also found in the soil, and some arsenic, therefore, is contained in foods. To avoid arsenic toxicity, stay away from insecticides and weed killers that contain arsenic. In addition, if you drink well water, check to make sure it doesn’t contain any significant levels of arsenic or other toxic metals.

  Your kidneys eliminate arsenic from your body, but excess amounts may adversely affect the kidneys, the heart, and the blood cells as well.

  Small amounts of arsenic may even be essential to human health, but more research is necessary to verify this.

• Cadmium: Exposure to cadmium comes through cigarette smoke, certain paints, water, coffee, tea, and contaminated foods, specifically refined grains. Cadmium occurs in the earth, commonly along with zinc. It may interfere with zinc functions in the body, affecting immunity, prostate health, and bones.

  To prevent cadmium toxicity, avoid exposure to cigarette smoke, contaminated seafood, and refined foods, while maintaining good levels of zinc in the body.

  Cadmium causes mild to moderate toxicity in humans and may affect the kidneys and blood pressure, because it is a factor in hypertension. This heavy metal is not as toxic as lead and mercury, because cadmium does not appear to get into the brain.

  Chelation therapy (an intravenous vitamin therapy to pull metal from body tissues) and zinc supplements can reduce cadmium toxicity. Copper, iron and selenium and vitamin C can help eliminate cadmium as well.

(http://www.dummies.com/how-to/content/toxic-minerals-to-avoid-in-food-and-environment.html)

Toxicology and Effect of Mineral...

Very few epidemiological studies have been conducted to determine the relationship between minerals and the incidence of cancer in humans. This is due partly to the difficulty of identifying populations with significantly different intakes of the various minerals. In contrast, there have been numerous studies in laboratory animals. In these investigations, the carcinogenic effects of many metals, administered at high doses to the animals parenterally, have been well established and have been reviewed extensively (Furst, 1979; Sunderman,1977). However, the results of these studies have shed little light on the potential carcinogenic risk posed by trace elements in the amounts occurring naturally in the diet of humans.

Very few feeding studies have been conducted to test the carcinogenicity of trace elements in animals. The carcinogenic action of these elements is difficult to test in animals because some of them are toxic at levels that exceed dietary requirements, and because it is difficult to control synergistic interactions of the element under investigation with other elements that may contaminate air, diet, and drinking water. This chapter contains an evaluation of a few of those trace elements that are nutritionally significant and suspected of playing a role in carcinogenesis. The committee sought evidence primarily from those experiments in which the element was fed

to the animal or from epidemiological reports of exposure through diet. Results obtained from laboratory experiments using other routes of exposure, or evidence from occupational exposure of humans, are described briefly when sufficient information about dietary exposure could not be found. The effects of both the deficiencies as well as excessive intakes of minerals are also discussed in this chapter. Schroeder and his associates investigated the carcinogenicity of trace elements in a series of large experiments extending over 15 years (Kanisawa and Schroeder, 1967; Schroeder and Mitchener, 1971a,b, 1972; Schroeder et al., 1964, 1965, 1968, 1970). Animals were raised in an environment that permitted maximum control of trace element contamination; they were fed one diet of known composition; and they were observed

for their lifetime. The following elements were studied in at least 50 mice and/or rats per treatment: fluorine, titanium, vanadium, chromium, nickel, gallium, germanium, arsenic, selenium, yttrium, zirconium, niobium, rhodium, palladium, cadmium, indium, tin, antimony, tellurium, and lead. These elements were added to the drinking water at levels of 5 mg/liter, except for selenium (3 mg/liter) and tellurium (2 mg/liter). These levels (approximately 100 times greater than the concentrations present naturally in the diet) did not significantly affect

growth and survival of the animals. The interpretation of these findings of no effects or minimally significant effects must be cautious, in view of the small number of animals used. Only rhodium and palladium (tested in mice only) showed any signs of carcinogenicity, but as Schroeder and Michener (1971a) stated, “The results were at a minimally significant level of confidence.” Further studies are needed to confirm these findings. Schroeder also reported that selenate, but not selenite, increased the incidence of spontaneous malignant mammary and subcutaneous tumors in rats after lifetime exposure (11 in 75 controls vs 20 in 73 selenate-fed animals). These results were not confirmed in similar studies in mice. (The effects of selenium on carcinogenesis are discussed in further detail below.) None of the remaining elements examined increased tumor incidence. A significant reduction in tumor incidence was observed in mice fed arsenic and cadmium and in mice and rats fed lead.

http://www.nap.edu/catalog/371.html

Silica Gel, MCM, and Activated Alumina

From the e-book, that I see, define of different silica gel, MCM, and activated alumina. What’s is them…? Let’s see…

Silica gel is the most widely used desiccant because of its large capacity for water (40% by weight) and ease in regeneration (∼150 ◦C, compared with 350 ◦C for regenerating zeolites). In addition, its surface can be readily modified by reacting (or grafting) with a monomolecular layer of organic ligand, and these modified silica gels are being applied in an increasing number of applications in chromatography. All aspects of silica gel and its modification have been reviewed

and discussed extensively (Iler, 1979; Unger, 1979; Vansant et al., 1995). The MCM-type materials belong to a new family of ordered, mesoporous silicate/aluminosilicate prepared by hydrothermal formation of silica gels in the presence of surfactant templates (Beck et al., 1992). They were discovered only recently, by Beck et al. in 1992, and hold promise for a number of interesting applications. Hence they are included in this chapter. Activated alumina is also widely used as a desiccant because of the same advantages for which silica gel is used. Unlike silica gel, which is amorphous, activated alumina is crystalline. Oxygen vacancies (defects) are easily formed on its surfaces, thus alumina has both Lewis and Brønsted acid sites. The surface

chemistry, as well as the pore structure of activated alumina, can be modified, for example, by treatment with acid (HCl or HF) or alkaline (to alter the acidity) and controlled thermal treatment (to tailor the pore structure). As a result, activated alumina is more versatile than silica gel and has been applied more often as a sorbent.

Adsorbent, fundamentals and application, Yang, R.T., John Wiley and Son’s

The HSAB (Hard Soft Acid Base) Theory

HSAB is an extremely useful qualitative theory that enables predictions of what adducts will form in a complex mixture of potential Lewis acids and bases. Although there have been numerous attempts to make the theory quantitative by assigning numbers representing "hardness" and "softness" to acids and bases, these have not been particularly successful. Even if only qualitative, the theory is so useful that it is essential to know something about it. Fundamentals. The basic premise of Hard/Soft Acid/Base Theory is very simple: Hard acids prefer hard bases; soft acids prefer soft bases. We must now define these terms.

Hard acids (in context, HA) are characterized by (s,f blocks, left side of d block in higher OS's)

Low electronegativity of the acidic atom.

A value in the range 0.7-1.6 is typical of hard acids;

Relatively small size; Relatively high charge (> 3+).

High charge often results in small size, because the remaining electrons are contracted toward the nucleus by the substantial excess positive charge. Specific examples of hard acids are the metal cations from the s and f blocks, and the higher-charged ions from the left side of the d block. Na⁺, Mg²⁺, Fe³⁺, and Al³⁺ are examples of hard acids.

Hard bases (in context, HB) are characterized by

Very high electronegativity of the donor atom (in the range 3.4-4);

Relatively small size of the donor atom.

The combination of high electronegativity and small size results in a nonpolarizable electron cloud surrounding the donor atom. The only 2 donor atoms with electronegativities in the specified range are oxygen and fluorine. So the hard bases are those in which the donor atom is either O or F. Specific examples are O^2-, F^-, OH₂, CO₃^2-, and PO₄^3-.

Soft acids (in context, SA) are characterized by an acceptor atom of

intermediate to high (1.9-2.5);

large size;

low charge (1+, 2+)

Species of large size generally have many electrons, some of which can be quite far from the nucleus. The low charge of the species results in a polarizable (distortable) electron cloud. Specific examples of soft acids include Cu⁺, Hg²⁺, Au⁺, Ag⁺, and Pb²⁺. Note that these metals are all clustered in the same region of the periodic table.

Soft bases (in context, SB) are characterized by donor atom of

intermediate to high electronegativity (2.1-3.0)

large size, leading to polarizability

Specific examples of soft bases are S^2-, RSe^-, I^-, and Br^-. Note that these fall in groups 15-17 in periods with n > 3.

In addition to the fundamental "hard" and "soft" categories, two additional categories are useful. Borderline acids (in context, BA) are intermediate between hard and soft acids. Thus they tend to have lower charge and somewhat larger size than hard acids, and higher charge and somewhat smaller size than soft acids. The 2+ ions of the d block, such as Fe²⁺, Cu²⁺, Ni²⁺, and Zn²⁺, are borderline acids. Borderline bases (in context, BB) are intermediate between hard and soft bases. They tend to be larger and less electronegative than hard bases, smaller and more electronegative than soft bases. Bases in which the donor atom is N or Cl fall in this category. Thus NH₃, Cl^-, RCl, and pyridine are borderline bases.

Example: Classify each species as Lewis acid or base; as hard, soft, or borderline. Which of the Lewis bases would prefer to form adducts with each of the acids?

Fe³⁺ : this has high positive charge, so is expected to be a hard acid.

I^- : This is a large anion with low electronegativity and low charge; it is expected to be a soft base.

CH₃^- : This is an anion, so is probably a base. The donor atom has low electronegativity and relatively low charge. Even though the donor atom is fairly small, this behaves as a soft base.

CO₃^2-: This is an anion with oxygen atoms as potential donors. It is a hard base.

Cu⁺ : This is a transition metal cation with a low charge. It is expected to be a soft acid.

Cl^- : This is an anion with a chlorine donor atom. It should be a borderline base.

Se(CH₃)₂F^- : This is an anion with two potential donor atoms: F, which is a hard donor; and Se, with two electron pairs, which is expected to be a soft base. This species is definitely a base, but can be soft or hard depending on circumstances.

We predict that Fe³⁺ should prefer to form adducts with the carbonate anion and the F donor of Se(CH₃)₂F^-. Cu⁺ should prefer adducts with the soft bases, I^- and CH₃^-. Cl^- will probably bind to either the hard or soft acid, but would prefer a borderline acid such as Fe²⁺.

Because hard acids and bases tend to be highly charged and nonpolarizable, the interaction between them is largely ionic. Their small sizes allow the acid and base to get close enough together so that the ionic interaction is quite strong (remember Coulomb's Law: force of attraction increases as the attracting species get closer together). A good image to keep in mind when thinking of a hard acid/hard base adduct is the juxtaposition of a golf ball (the "acid") with a baseball (the base). Both of these items are small, hard, and undistortable (try pushing the golf ball and baseball together--what happens?). In contrast, soft acids and soft bases have covalent interactions because their electron clouds are polarizable. A good image for soft-soft interactions is the juxtaposition of a large nerf ball (the base) with a smaller nerf ball (the acid). Here the electron clouds are squishy, and can be easily distored during the interaction.

Pearson, 1960

Gula itu manis, Garam itu asin, tapi....

Siapa yang tak kenal gula...? zat yang tidak berbau dan berasa manis, sering digunakan untuk membuat minuman, dikeroyokin semut kalo gag ditutup, begitulah gula..
Gula dibuat dari tetes tebu (wah, maap gag tau prosesnya..). hehe. Tapi yang jelas, gula dalam dunia kimia adalah sukrosa. Sukrosa merupakan gabungan dari beta-glukosa dan alfa-fruktosa (organik banget sich...). Rumus umumnya C11H22O12.
Tapi kenapa kita bahas gula yach...?
Di sini akan dibahas (cie..., dibahas..) tentang gula Vs garam. Dari rasanya, ughhh... jelas banget bedanya. Manis Vs Asin.... Dari ikatan yang terjadi jelas beda. Garam, sebut saja NaCl, mempunyai ikatan ionik dengan bentuk kubistik rigid, sedang gula ikatannya kovalen.
Terus, mengapa ketika gula dilarutkan dalam air, dengan pemanasan hilang semua, sedang larutan garam ketika dipanaskan didapat garamnya kembali...? Mekanisme ini terjadi karena pada gula, terdapat gugus hidroksil (OH). gugus hidroksil ini akan berikatan secara elektronik dengan gugus hidroksil pada air, sehingga membentuk ikatan OH anta gula dengan air. Keadaan ini menyebabkan gula dan air bersifat homogen, karena ikatan OH tersebut. Ikatan tersebut tidak dapat dipisahkan dengan pemanasan, selayaknya pemutusan ikatan OH pada H2O dengan pemanasan. Efeknya, hanya berpengaruh pada bentuk (fasanya) saja. Jadi, gag mungkin didapat gula dari larutan gula dengan pemanasan.
Berbeda dengan garam NaCl dan garam-garam lain. Na-Cl memiliki ikatan ionik. Ikatan ini mudah putus, dengan hanya membutuhkan energi yang kecil. Dengan pelarutan pada air (solvasi), ikatan ionik ini dapat putus membentuk ion-ionnya. Pelarutan ini hanya menyebabkan terbentuknya ion-ion penyusun NaCl. Ketika diberikan energi lebih (pemanasan), maka NaCl bisa didapat kembali. Ini bisa dilihat, untuk mendapatkan garam dari air laut, cukup dipanaskan.
Lalu bagaimana cara membuat gula batu (beda ma caramel gula lho....)....?
Gula batu sebenarnya hampir sama dengan gula biasa. Pembuatannya mudah, tetapi tidak dengan pemanasan. Caranya, larutkan gula pada air panas. Kemudian julurkan benang pada larutan gula tersebut (boleh dipegangi, boleh juga digantung pada seutas kawat atau apa aja). Diamkan ada kondisi kamar. Lihat setelah dingin, maka akan akan gumpalan-gumpalan putih gula batu. Ini terjadi karena kristalisasi (tau khan..?) Yaitu pemurnian senyawa pada kondisi panas untuk melarutkan pengotor. Dengan hal tersebut, gula batu bisa diambil..
Bagaimana....?

Spektra Silika Gel

Silika Gel sebagai adsorben, telah dikenal luas dalam dunia kimia. Struktur polimernya yang amorf (tidak tertata), gabungan dari agregat-agregat Si-OH yang membentuk polimer terarah Si-O-Si, menjadikan senyawa adsorben ini memiliki kstabilan yang cukup baik.
Pemanasan tidak mengubah struktur silika gel, bahkan ketika silika gel telah dirasa jenuh, pemanasan sering dilakukan untuk mengeluarkan/memutus ikatan H2O dari surface silika gel.
Silika gel banyak diproduksi oleh vendor terkenal, selevel Merck, Flucka dan sebagainya. Standar Kiesel 60 dan G60 banyak menjadi pilihan alternatif pengambilan silika gel untuk penelitian. Berbeda dengan jenis silika gel konvensional berwarna biru, Silika gel Kiesel G60 berwarna putih, serbuk halus, dan ringan.
Untuk mengetahui karakterisasi silika gel, sering dipergunakan IR-Spectroscopy dalam pengenalan gugus fungsinya. Seperti terlihat pada gambar di bawah. Mungkin, sedikit Site yang menyediakan spektra ini lho, sudah saya check, dan ini saya uji IR-Spectroscopy sendiri, bukan download dari suatu situs (^_^)

Dalam memahami spektra yang muncul, tiap bilangan gelombang boleh dibaca semua, tetapi kebanyakan yang memiliki intensitas serapan yang baik yang dibaca. Seperti contoh, pada bilangan gelombang 3402,43 cm-1, merupakan serapan -OH dari gugus alkohol silanol (Si-OH). Serapan ini berada pada kisaran 3400-3450 cm-1. Kemudian serapan pada bilangan gelombang 1602,21 cm-1, merupakan serapan khas dari -OH dari konformasi H2O, fingerprint yang muncul dari serapan ini dideteksi pada bilangan gelombang 802,39 cm-1. Fingerprint adalah sidik jari, spektra penguat dari suatu serapan gugus fungsi. Kebanyakan, fingerprint/overtone berada pada 1/2 nilai spektra yang kuat. Spektra selanjutnya yang dibaca adalah serapan pada bilangan gelombang 1111,00 cm-1. Serapan ini sangat khas, dengan titik puncak bawah yang curam, menekankan intensitas gugus fungsi yang banyak. Serapan ini menunjukkan gugus fungsi Si-O-Si, yang merupakan gugus siloksan penghubung antara tiap konformasi silanol.
Seperti itulah contoh pembacaan spektra Infra Merah dari silika gel...

_Isotherm Langmuir...??

Skripsi saya tentang adsorpsi, peningkatannya oleh silika gel termodifikasi ligan. Dalam pengujian adsorpsi, untuk mengetahui apakah adsorpsi tersebut termasuk adsorpsi fisik atau kimia, maka hasil pengujian diplotkan terhadap grafik, yang ditentukan dari Persamaan Langmuir (isotherm). Persamaan ini mengacu pada jumlah mol sampel yang terikat pada suatu adsorben pembandingannya terhadap konsentrasi akhir. Namun, banyak referensi jurnal mengetengahkan, pembandingan jumlah mol tersebut, harusn melalui konsentrasi akhir dahulu sebelum pembandingan terhadap konsentrasi akhir sampel yang sama. Jadi, terdapat 2 perbandingan.
Sebenarnya, yang mana yang benar...?
Ce/q Vs Ce ataukah q Vs Ce..?