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All Journal Jurnal Penelitian Saintek Jurnal Sains Dasar
Heru Pratomo
Department Of Chemistry, Faculty Of Mathematics And Natural Science, Universitas Negeri Yogyakarta
Decision Sciences, Operations Research & Management Education

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DETERMINING ISOSBESTIC POINT AND DETERMINATION OF P-NITROFENOL COMPOUND by SPEKTROFOTOMETRI Heru Pratomo
Jurnal Penelitian Saintek Vol 8, No 1: April 2003
Publisher : Institute of Research and Community Services, Universitas Negeri Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (4733.925 KB) | DOI: 10.21831/jps.v8i1.5479

Abstract

The determined of isosbestic point from weak acids or weak bases areusually important for  indicator solutions. The indicators that used in acid-base titration have pH exactly, and this is usefulfor determine the end of titration. The aims of this research are  (1)  to determine ofwavelength on isosbestic point of p-nitro phenol, and (2) to determine of dissociation constant of p-nitro phenol. The determined of isosbestic has  done  with  spectrophotometric  method,  to  the  p-nitro  phenol solutions in several pH, at region of wavelength between 280 nm - 450 nm. In this research, indicate that the isosbestic point ofp-nitro phenol at the wavelength of 348 nm, and pH about 6.7. From this research also can be determined that the dissociation constant (KaYof p-nitro phenol is 6.48 x 10-8,not too different compared with K, literature, is7.08 x 10-8.
MAKING MULTIPLE OF MULTI-POLY CULULOSE COMPOSITE POLYCULOSE FOR SEPARATION OF TEXTILE COLOR DYES Heru Pratomo
Jurnal Penelitian Saintek Vol 10, No 1: April 2005
Publisher : Institute of Research and Community Services, Universitas Negeri Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (7365.306 KB) | DOI: 10.21831/jps.v10i1.5472

Abstract

The purpose   of  this  work  is,  to  determine  the  role  of  supportcomposite polysuljone  -  cellulose  acetate  membrane  in separating textile dyes. The subject is the textile dyes, and the object is dispersing textile dyes. The solution  of the textile dyes (red, yellow  and blue) made as wastewater from  textile industry. It can be concluded that the support composite polysuljone  - cellulose acetate membrane showed good permeability and high permsefectivity in separating textile dyes.
Voltamogram Stainless Steel/Fe-Co-Ni dalam Media Tepung Ubi Jalar (Ipomoea batatas L.) Isana Supiah Yosephine Louise; Heru Pratomo Aloysius; Sulistyani Sulistyani
Jurnal Sains Dasar Vol 7, No 2 (2018): October 2018
Publisher : Faculty of Mathematics and Natural Science, Universitas Negeri Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21831/jsd.v7i2.11943

Abstract

Cyclic voltammogram of stainless steel/Fe-Co-Ni on base condition and on various sweet potato starch concentration could be used to study the electrocatalyst activity of stainless steel/Fe-Co-Ni. The efficiency is derived from the point of view of product and energy required, for instance comparing between stainless steel/Fe-Co-Ni and stainless steel.The research had conducted water electrolysis on base condition with several conditions, such as addition of 5 grams NaHCO3 per liter of water, sweet potato starch as medium on various concentration (0 - 10 grams per liter of water), and stainless steel/Fe-Co-Ni as a working electrode. The research methodology which is used is cyclic voltammogram using eDAQ EChem as the voltameter instrument.Based on the cyclic voltammograms, it could be concluded that sweet potato starch causes covering around the electrode surfaces so water molecule splitting process would be obstructed. The optimum covering point is occurred on the addition of 9 grams sweet potato starch per liter of water. The optimum condition is occurred on the addition of 4 grams sweet potato of starch per liter of water; with product efficiency is 1.62 times and energy saving as much as 6.90% compared with the utilization of stainless steel as electrode. Keywords: voltammogram, sweet potato, stainless                  steel/Fe-Co-Ni, covering, efficiency.
Co-Authors Isana Supiah Yosephine Louise Sulistyani Sulistyani