Abstract:Sodium silicate is used as raw material for several purposes: silica gel production, preparation of catalysts, inks, load for medicines, concrete hardening accelerator, component of detergents and soaps, refractory constituent and deflocculant in clay slurries. In this work sodium silicate was produced by reacting rice hull ash (RHA) and aqueous sodium hydroxide, in open and closed reaction systems. The studied process variables were time, temperature of reaction and composition of the reaction mixture (expres… Show more
“…Sodium silicate, for example, is currently obtained industrially by melting sand with sodium carbonate at high temperature between 1300˚C -1500˚C [12] [13]. This manufacturing process consumes large amount of energy and produces considerable air pollutants such as dust, nitrogen oxide and sulfur oxide [13].…”
Section: Introductionmentioning
confidence: 99%
“…Hence, it leads to serious environmental pollution issues derived from its disposal. RHA contains more than 60% of silica [12] [13]. The nature of this silica depends on the burning temperature.…”
High cost has been pointed among factors that limit the promotion of geopolymers. To contribute to the reduction of the use of costly industrial sodium silicate in activators for geopolymers, a gel obtained with RHA and concentrated sodium hydroxide was used in the present study to develop an alkaline activator with 8 M NaOH and to produce geopolymers with crushed fired clay bricks wastes (FCBW). Characteristics of the gel were compared to that of commercial sodium silicate which was also mixed with 8 M NaOH in the ratio 1:1 to produce geopolymers. Chemical and mineralogical analyses were done on raw materials. Fourier Transformed Infrared Spectroscopy (FTIR) was done on the gel, commercial sodium silicate and products. Biaxial four point flexural strength, bulk density, water absorption and scanning electron microscopy (SEM) tests were also done on products. Results showed that RHA-NaOH alkaline activator has good potential in consolidating FCBW powder through geopolymerization process which gave products that had characteristics not far from that when the commercial sodium silicate was used. The gel obtained by mixing RHA and NaOH can contribute to the reduction of the use of costly commercial sodium silicate in the production process of geopolymers. However, appropriate filtration process is needed for the RHA-NaOH gel to reduce its impurities as undissolved entities, which will consequently contribute to improve the flexural strength, the density and the microstructure of its products which were low compared to when commercial sodium silicate was used.
“…Sodium silicate, for example, is currently obtained industrially by melting sand with sodium carbonate at high temperature between 1300˚C -1500˚C [12] [13]. This manufacturing process consumes large amount of energy and produces considerable air pollutants such as dust, nitrogen oxide and sulfur oxide [13].…”
Section: Introductionmentioning
confidence: 99%
“…Hence, it leads to serious environmental pollution issues derived from its disposal. RHA contains more than 60% of silica [12] [13]. The nature of this silica depends on the burning temperature.…”
High cost has been pointed among factors that limit the promotion of geopolymers. To contribute to the reduction of the use of costly industrial sodium silicate in activators for geopolymers, a gel obtained with RHA and concentrated sodium hydroxide was used in the present study to develop an alkaline activator with 8 M NaOH and to produce geopolymers with crushed fired clay bricks wastes (FCBW). Characteristics of the gel were compared to that of commercial sodium silicate which was also mixed with 8 M NaOH in the ratio 1:1 to produce geopolymers. Chemical and mineralogical analyses were done on raw materials. Fourier Transformed Infrared Spectroscopy (FTIR) was done on the gel, commercial sodium silicate and products. Biaxial four point flexural strength, bulk density, water absorption and scanning electron microscopy (SEM) tests were also done on products. Results showed that RHA-NaOH alkaline activator has good potential in consolidating FCBW powder through geopolymerization process which gave products that had characteristics not far from that when the commercial sodium silicate was used. The gel obtained by mixing RHA and NaOH can contribute to the reduction of the use of costly commercial sodium silicate in the production process of geopolymers. However, appropriate filtration process is needed for the RHA-NaOH gel to reduce its impurities as undissolved entities, which will consequently contribute to improve the flexural strength, the density and the microstructure of its products which were low compared to when commercial sodium silicate was used.
“…A síntese de zeólitas pode ser realizada por qualquer matéria prima que contenha predominância de sílica e alumina, como por exemplo, argilas e cinzas da casca de arroz (Baccouche et al, 1998;Maia et al, 2007;Mignoni et al, 2007;Foletto et al, 2009;Rahman et al, 2009). No entanto, o uso de cinza de carvão é mais explorado devido à quantidade significativa desse resíduo gerado ao redor do mundo.…”
“…Selain mengandung K, abu sekam diketahui mengandung Si yang tinggi. Abu sekam mengandung 94,4% (SiO 2 ), 0,61% (Al 2 O 3 ), 1,06% (K 2 O), 1,21% (MgO), 0,77% (NaO), 0,59% (MnO), 0,83% (CaO), 0,03% (Fe 2 O) (Foletto et al, 2006). Silikat dapat mengurangi efek negatif ter-hadap kelebihan pemupukan N, namun mening-katkan ketersediaan unsur P dengan mencegah fiksasi P dalam komplek serapan dan mengurangi kelebihan serapan Fe dan Mn (Marschner, 2012).…”
ABSTRAKKemuning (Murraya paniculata) telah digunakan secara tradisional sebagai tanaman obat karena mengandung metabolit sekunder yang memiliki berbagai fungsi. Pemupukan dengan pupuk organik dan interval panen dapat meningkatkan produksi metabolit sekunder, terutama flavonoid. Tujuan penelitian untuk mengetahui pengaruh kombinasi dosis pupuk organik dan interval panen yang berbeda terhadap produksi flavonoid daun kemuning. Penelitian dilaksanakan sejak Juni 2014 sampai Februari 2015 di Kebun Percobaan Organik IPB, Cikarawang, Bogor. Percobaan disusun berdasarkan Rancangan Acak Kelompok (RAK) faktorial dengan faktor (1) pupuk organik menggunakan 8 kombinasi dosis pupuk kandang ayam (PA) dan abu sekam (AS) yaitu kontrol; 0 kg PA + 3 kg AS; 7 kg PA + 0 kg AS; 7 kg PA + 3 kg AS; 14 kg PA + 0 kg AS; 14 kg PA + 3 kg AS; 21 kg PA + 0 kg AS; 21 kg PA + 3 kg AS pertanaman dan (2) 3 interval panen (2, 3, dan 4 bulan). Data dianalisis menggunakan uji F dan taraf DMRT 5%. Hasil penelitian menunjukkan bahwa pemberian kombinasi dosis pupuk organik dengan berbagai dosis yang berbeda tidak memberikan pengaruh nyata (P>0,05) terhadap semua parameter yang diamati. Perlakuan interval panen nyata meningkatkan produksi daun berupa berat basah dan kering daun total pada interval panen 4 bulan masing-masing sebesar 914,92 g tanaman -1 , 258,53 g tanaman -1 . Perlakuan interval panen memberikan pengaruh terhadap produksi senyawa flavonoid total, antosianin, protein, klorofil total, dan aktivitas antioksidan. Interval panen 2 bulan menghasilkan klorofil total tertinggi sebesar 1,72 mg g BB -1 . Interval panen 4 bulan menunjukkan aktivitas enzim PAL (7,915 x 10 -5 mg CA eq g BB -1 ), produksi protein (7,96 mg tanaman -1 ), flavonoid total (682,82 mg tanaman -1 ), antosianin (1,17 mg tanaman -1 ), dan aktivitas antioksidan (76,51%) tertinggi. Tidak ada interaksi antara pemberian pupuk organik dengan interval panen semua parameter pengamatan.
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