This study aimed to create nano vegetable tanning materials of acacia bark extract. The process started with size reduction of acacia bark (16.7 mm x 4.9 mm x 1.8 mm), followed by counter current extraction of acacia bark with water at 80ºC with 1:3 bark to water ratio in order to obtain extracts with density of 9-10ºBe. Drying was done with a spray dryer. Particle size of the resulting powders was measured with particle size analyzer. Planetary ball mill was used for 6 hours to obtain average particle size of 72.9 nm. A variety of vegetable tanning materials were applied in the vegetable tanning process with varied concentrations of 15, 20, and 25%. The use of 25% nano vegetable tanning material of acacia bark extract gave the best results compared to liquid extract of acacia bark and mimosa. The properties of the leather obtained were tensile strength of 27.04 kg/cm 2 , elongation at break of 50%, shrinkage temperature of 84 o C, and degree of tannage of 79.65%.

The aim of this study is to reduce ammonia concentration in tannery wastewater using bagasse fly ash in a batch adsorption system. Experiments were conducted to study the effect of various parameters such as adsorbent dose and contact time. Data analysis was performed by calculating the efficiency of adsorption and fitting the data into Freundlich and Langmuir isotherm models. Correlation coefficient and mean squared error were used to evaluate the performance of the models. From the results, it was found that the operating conditions to achieve an optimum removal efficiency of 45.72% are 1 hour contact time and 2 grams of bagasse fly ash. The results also indicate that the data fits Langmuir model well where Langmuir constant Q o , b, and correlation coefficient were found to be 0.706 mg/g, 0.209 L/mg, and 0.9424, respectively.

Optimization of the reaction time on the formation of indofenol blue complex for N-Ammonia analysis in the tannery PENDAHULUANAmonia adalah suatu senyawa nitrogen yang banyak digunakan untuk produksi berbagai komoditi seperti pupuk, obat-obatan, dan lain-lain. Di alam amonia berasal dari air buangan industri (Ashrafizadeh and Khorasani, 2010) dan biodegradasi senyawa organik secara mikrobiologis (Li et al., 2013). Salah satu industri penghasil amonia adalah industri penyamakan kulit. Industri penyamakan kulit dalam operasinya menghasilkan limbah cair, padat dan gas. Limbah cair merupakan limbah yang paling banyak dibuang oleh industri penyamakan kulit. Menurut Gubernur Kepala

Unsaturated polyester is applied in many products such as aircraft sections, boats, building panels, automotive accessories and modifications, etc. In this research, unsaturated polyester was used as a raw material, which was reinforced with a fiberglass mat, and casted in a silicon rubber mold. The concentrations of methyl ethyl ketone peroxide ( 1-3 phr) as an initiator and cobalt naphtanate (0-2 phr) as an accelerator were used in the preparation of safety helmet. Subsequently, the effects of the compounds to the reaction time, the brittleness ofthe products, and the physical properties, were studied. The results showed that the compound composed by 100 phr unsaturated polyester, 2 phr methyl ethyl ketone peroxide, 2 phr cobalt naphtanate, 40 phr silica, 20 phr fiberglass mat and I phr pigment was not brittle, had a good reaction time and nonflammable, gave 4.82 mm in resistance to penetration, and the deflection of A and B were 4.5 and 0.0 mm, respectively.

Penelitian bertujuan untuk mendapatkan formulasi kompon oil seal yang optimum dengan menggunakan karet nitril. Dalampenelitian ini dibuat rancangan percobaan dengan 2variasiyaituperbandingankaretnitril lLarctalanTOl2O;/5/15;80/10danjumlah bahan pengisi carbon black 45 ;hr, 50 phr danf 5 phr. Kompon-dibuat dalam mesin two roll mill' kemudian divulkanisasi paia r,rfr' tSO'C,iekanan iSO tgl"-' dan waktu sesuai dengan yang ditunjukkan oleh curometer. Dari 9 formulasi yang diteliti diperoleh formulasi kompon oil seal terbaik dan memenuhi persyaratan JIS.9-.2402-76, terdiri atas karet nitril 70 phr' karet alam 20 phr, karet sBR 10 phr, carbon black 55 phr, DOP 15 phr, coumaron resin 5 phr, asam stearat 1 phr, zink oksida S pt,, vuttanox HS2 phr, paraffin wax 0,8 phr' minyak aromatik 6 phr, cBS 1,2 phr, TMT 0,1 phrNeoblend 2 phr dan sulfur 1,5 phr; dengan sifat fisis kekeras an6l,7 shore A, tegangan putus 12,01 Nimnf' perpanjangan pYlT 383'8o/o' pampat tetap 45,62yo,perubah* 'gt"_ruiperendaman d"t_"*oli SAE 50w, 100oc, 72 jam : perubahan kekerasan 4,32Yo;perubahan te gangan put us | 6,3 SYo;perubahan perpanj angan p.rtl.rt 17,13%o; dan perubahan volume l,38oh'