AbstrakTujuan penelitian ini adalah mengetahui pengaruh pH pada adsorpsi kation unsur hara Ca 2+ dan K + silika lumpur lapindo hasil pemisahan. Data dikumpulkan melalui eksperimen adsorpsi, dimana 3 gram silika hasil pemisahan lumpur Lapindo dilarutkan dalam 300 mL larutan yang berisi Ca 2+ atau K + 0,0001 M atau 0,001 M, dan diaduk selama waktu kesetimbangan, yaitu 2 jam. pH suspensi divariasi dan dibiarkan 2 jam, sampel diambil dan diukur konsentrasi kation bebas dalam larutan dengan Atomic Absorption Spectrophotometry untuk Ca 2+ dan Flame Atomic Emission Spectroscopy untuk K + . Variasi pH dilakukan dari 3 hingga 10 dengan suhu dan waktu kontak dipertahankan 30 o C dan 2 jam. Hasil penelitian menunjukkan kedua kation tersebut terikat dengan pola sigmoid, membesar seiring dengan meningkatnya harga pH. Pada semua harga pH yang teramati, Ca 2+ dan K + . terikat dalam jumlah yang tidak berbeda secara signifi kan. Sorben silika dalam air membentuk silanol (SiOH) yang terprotonasi pada pH rendah, membentuk SiOH 2 + dan terdeprotonasi pada pH tinggi menjadi SiO¯. Baik Ca 2+ maupun K + . diikat melalui reaksi pertukaran kation dimana Ca 2+ atau K + . menggantikan proton H+ dari gugus -OH silanol membentuk [SiO(CaOH)] untuk Ca 2+ , dan [SiO-K] untuk K + . AbstractThe aim of this research was to determine the effect of pH on the adsorption of micronutrients of Ca 2+ and K + . by silica from lapindo mud. Data were collected by the adsorption experiments, on which 3 grams of silica separated from Lapindo mudwere dissolved in 300 mL of 0.0001 or 0.001 M Ca 2+ or K + ., and stirred for 2 hours. The pH of suspension was varied and left for equilibrate for 2 hours, and a sample was taken and measured for free concentration of K + .cation using Flame Atomic Emission Spectroscopy and of Ca 2+ using Atomic Absorption Spectroscopy (AAS). The pH ranges were from 3 to 10. Temperature of 30 o C and contact time of 2 hours were maintained. The research showed that both cations were adsorbed in sigmoid curve, increased with increasing pH values. In entire ranges of observed pH, the percentage of cations adsorbed by silica was not different signifi cantly. The adsorbent of silica formed silanol (SiOH) in water. The -OH groups of silica were protonated forming SiOH 2 + at lower pH and deprotonated forming SiO¯at higher pH. Wether Ca 2+ or K + . cations were bound to silica surfacesvia cation exchange reactions,
TITLEThe effect of honey water consumption to acidity level of pH saliva in elementary school childrenABSTRACTCommunities can take advantage of traditional medicine such as honey as an alternative medicine to reduce the formation of dental plaque. Honey containing antibiotics as antibacterial and antiseptic keeping the wound. Natural honey contains a lot of enzymes, that is very complex of protein molecul, produced by living cells and have function as catalyst, which is : The speed reaction modifier substance in the chemical process. The process happened within the body of every living beings. Based on preliminary studies to 10 students saliva examination average student salivary pH less than 7 below normal, and students have an average of dental caries 2. Research objective is to know the average level of acidity pH of saliva before and after drinking honey.Quasi-Experimental research type, research using pretest-posttest design With Control Group. Total sample of 60 students, by means of random sampling. Test analysis by T-Test.PH study results before and after drinking the honey of significance is p = 0.05 0.05. The conclusion of this study was there was the influence of drink honey to salivary pH values. Keywords : drink honey, the pH of saliva
In this research, adsorption of Ca(II), Pb(II) and Ag(I) in aqueous solution onto sulfonato-silica hybrid (SSH) prepared from rice hull ash (RHA) has been studied. The preparation of SSH adsorbent was carried out by oxidation of mercapto-silica hybrid (MSH) with hydrogen peroxide (H2O2) solution 33%. MSH was prepared, via sol-gel process, by adding 3 M hydrochloric acid solution to mixture of sodium silicate (Na2SiO3) solution and 3(trimethoxysilyl)-1-propanthiol (MPTS) to reach pH of 7.0. Solution of Na2SiO3 was generated from destruction of RHA with sodium hydroxide solution followed with heating at 500 °C for 30 min. The SSH produced was characterized with Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analyzer, energy dispersive X-ray (EDX) spectroscopy and determination of ion-exchange capacity for sodium ion (Na+). The adsorption of Ag(I) and Ca(II) were conducted in a batch system in various concentrations for one hour. The adsorbent ion was calculated based on difference of concentrations before and after adsorption process determined using atomic absorbance spectrophotometric (AAS) method. The adsorption character was evaluated using model of isotherm Langmuir and Freundlich adsorption to calculate the capacity, constants and energy of adsorption. Result of characterization by EDX and FTIR showed qualitatively that SSH has been successfully synthesized which were indicated by appearance of characteristic absorbance of functional group namely silanol (Si-OH), siloxane (Si-O-Si), methylene (-CH2-) and disappearance of mercapto group (SH). The XRD data showed amorphous structure of SSH, similar to silica gel (SG) and MSH. The study of adsorption thermodynamics showed that oxidation of MSH into SSH increases the ion-exchange capacity for Na+ from 0.123 to 0.575 mmol/g. The change in functional group from silanol to mercapto and from mercapto to sulfonato increases the adsorption capacity of Ca(II). However, the capacity order of adsorbents for both ions of Pb(II) and Ag(I) in aqueous solution is MSH > SG > SSH.
Saliva menjadi salah satu faktor yang mempengaruhi proses terjadinya karies, karena saliva selalu membasahi gigi geligi sehingga mempengaruhi lingkungan dalam rongga mulut. Saliva berfungsi tidak hanya membantu dalam mengunyah makanan, tetapi juga berfungsi sebagai pelindung. Anak-anak sering mengkonsumsi makanan dan minuman yang mengandung karbohidrat, sehingga bakteri penyebab karies di rongga mulut akan memproduksi asam yang menyebabkan terjadinya demineralisasi. Di antara periode makan, saliva akan bekerja menetralisir asam dan membantu proses remineralisasi. Mengkonsumsi yoghurt dapat menjadi salah satu upaya untuk pencegahan karies pada anak. Yoghurt mengandung kalsium, yang bila dipertahankan lebih lama dalam saliva diharapkan dapat meembantu proses remineralisasi. Tujuan penelitian adalah untuk mengetahui pengaruh minum yoghurt terhadap pH saliva.
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