Judul: Studi Adsorpsi Logam Berat Seng (Zn) Dengan Menggunakan Akar Rambut Solanum nigrum L Galur A4
Abstrak: Sejak terjadinya tragedi pencemaran merkuri di Minamata, Jepang. perhatian terhadap pencemaran logam berat meningkat seiring dengan pyngembangan berbagai penelitian untuk menangani limbah logam berat. Di Indonesia pencemaran logam herat Zn telah melebihi ambang batas persyaratan kualitas air yang ditetapkan pada PP No. 20 tabun 1990. Fitoremediasi merupakan teknologi detoksifikasi limbah dengan menggunakan taoaman atau bagiannya yang merupakan metode efektif untuk mengatasi pencemaran limbah logam berat
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Judul: Kajian Pustaka Pemanfaatan Limbah Baglog sebagai Adsorben Logam Berat
Abstrak: Limbah industri mengandung berbagai senyawa kimia berbahaya seperti logam berat yang dapat mencemari lingkungan sehingga perlu disisihkan. Adsorpsi merupakan salah satu metode yang banyak digunakan karena lebih efisien dan ekonomis. Limbah baglog merupakan sisa budi daya jamur yang telah dilaporkan memiliki sifat sebagai adsorben. Kajian pustaka ini bertujuan menentukan pemanfaatan limbah baglog sebagai adsorben logam berat dengan perlakuan yang berbeda. Dalam kajian pustaka ini, metode adsorpsi menggunakan adsorben limbah baglog tanpa aktivasi kimia, dengan aktivasi kimia, dan pengarangan (biochar). Hasilnya menunjukkan bahwa adsorben limbah baglog tanpa aktivasi kimia mampu menjerap Fe, Mn, Ni, Cu, Pb, Zn, dan Cd dengan rentang kapasitas adsorpsi 0,0724–0,769 mmol/g. Adsorben limbah baglog dengan aktivasi kimia mampu menjerap Cr, Cd, dan Pb dengan kapasitas adsorpsi 0,167–0,971 mmol/g dan adsorben limbah baglog dengan bentuk pengarangan menjerap Cd, Pb, Cu, dan Zn dengan kapasitas adsorpsi 0,417–1,92 mmol/g., Industrial waste contains various hazardous chemical compounds such as heavy metals that can cause environmental pollution that must be removed. Adsorption is one of the methods widely used because it is more efficient and economical. Spent mushroom substrates are the residue of mushroom cultivation (baglog) that have to been reported as adsorbents. This literature review aims to determine the utilization of the baglog substrates as heavy metal adsorbents with different treatments. In this literature review, the adsorption method used the baglog adsorbents without chemical activation, with chemical activation, and biochar. The results showed that the baglog substrates adsorbent without chemical activation could adsorb Fe, Mn, Ni, Cu, Pb, Zn, and Cd with an adsorption capacity range of 0.0724–0.769 mmol/g. The baglog adsorbent with chemical activation could adsorb Cr, Cd, and Pb with adsorption capacity of 0.167–0.971 mmol/g, and that of adsorbent in the form of biochar could adsorb Cd, Pb, Cu, and Zn with adsorption capacity of 0.417–1.92 mmol/g.
Keyword: adsorben, adsorpsi, limbah baglog, logam berat

Judul: Bifurkasi Hopf pada Model Siklus Bisnis Kaldor Kalecki tanpa dan dengan Waktu Tunda
Abstrak: Business cycle model is one of dynamical system models in economic. One of the business cycles model is Kaldor-Kalecki model. Kaldor-Kalecki business cycle model that is written in delayed defferential equations, is a business cycle model that involves gross product and capital stock of a company. In this paper Kaldor-Kalecki business cycle model is analyzed using both nondelay and delay in time of capital stock. By Taylor expansion for the time delayed model, an analysis of stability around the fixed points has been done. Furthermore, by using Hopf bifurcation theorem, it can be shown that there exists periodic orbits and limit cycle. In the nondelayed model, changing the parameter of goods market could lead to the occurrence of Hopf bifurcation and the existence of limit cycle. Similarly, for the delayed model, it has been shown that changing the time delay parameter may result in the occurrence of Hopf bifurcation and limit cycle.
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