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Fisika merapakan salah satu mata pelajaran wajib untuk dipelajari di tingkat sekolah menengah atas khususnya pada siswa yang mengambil kelas peminatan ilmu pengetahuan alam (IPA). Namun, pelajaran fisika menduduki peringkat terendah kedua pada ujian nasional terakhir. Hal ini dapat menurunkan tingkat efiskasi diri pada siswa, sehingga mempengaruhi proses dan hasil belajar mereka. Dilihat dari hal tersebut, dibutuhkannya sebuah peningkatan dalam dukungan baik dari guru, orang tua, dan lingkungan siswa. Penelitian ini bertujuan untuk mengetahui tingkat efikasi diri siswa. Jenis penelitian ini adalah mixed method dengan menggunakan metode wawancara, observasi, dan penyebaran angket. Populasi yang digunakan adalah guru dan siswa dengan sampel sebanyak 60 siswa. Penelitian ini menggunakan pendekatan kualitatif dengan metode analisis deskriptif. Hasil penelitian menunjukkan bahwa efikasi diri peserta didik sangat dipengaruhi oleh persepsi yang mereka miliki. Maka dari itu, sangat penting bagi tenaga pendidik untuk membangun persepsi yang dimiliki oleh peserta didik. Ada banyak cara bagi tenaga pendidik untuk membantu peserta didik meningkatkan efikasi diri yang mereka miliki, seperti pemberian motivasi, penggunaan model atau strategi belajar yang menarik, ataupun pemberian kesempatan kedua bagi peserta didik dan tidak menghakimi atas apapun jawaban yang mereka berikan. Dengan demikian peserta didik akan merasa lebih percaya diri saat mengemukakan pendapat yang berdampak kepada meningkatnya tingkat efikasi diri peserta didik.

The dyes of the textile dyeing industry wastewater are harmful to humans and the environment. They should be treated before discharging into the environment. The adsorption using the spherical activated carbon can be effective to reduce the dyes. The spherical activated carbon of 3-7 µm in diameter was successfully prepared from the waste bagasse liquid using the hydrothermal method. The activation of this carbon was carried out using the KOH solution. The optimum pH and contact time were achieved in 2 and 200 min, respectively. Adsorption kinetic for RhB on activated spherical carbon follows the second-order kinetics and its adsorption mechanism follows the Langmuir isotherm. The maximum adsorption capacity of spherical activated carbon to Rhodamine B was achieved in 64.52 mg/g.

Adsorption kinetics is part of adsorption and discusses the adsorption rate of an adsorbent on the adsorbate. Adsorption kinetics has an equation to determine the rate constant of adsorption, namely the pseudo-first order and pseudo-second order. In this study, methylene blue was adsorbed using a C-4-hydroxy-3-methoxyphenylcalix[4]resorcinarene (CHMFKR) adsorbent. The aim of this study to determine the effect of process parameters (concentration, pH, and processing time) on the process adsorption, with the Langmuir and Freundlich adsorption isotherm model approach, and to determine the adsorption kinetics of methylene blue with CHMFKR. Ten mL of methylene blue solution with various concentrations of 5, 6, 8, 10, and 11 ppm with a solution pH of 7 was added to as much as 0.001 gram of CHMFKR adsorbent and stirred at 600 rpm for 40 minutes. The solution was measured, and its absorbance was measured using the UV-Vis Spectrophotometer. The results show that the adsorption kinetics follow pseudo second order with an adsorption rate of 0.7217 ± 0.4 g/mg.s. The adsorption isotherm follows the Langmuir equation, and the maximum adsorption amount is 114.94 ± 2.04 mg/g.

Industri etanol merupakan salah satu industri yang menimbulkan pencemaran terhadap lingkungan khususnya sistem perairan. Banyaknya limbah cair etanol yang dibuang serta senyawa-senyawa organik dapat menyebabkan rusaknya ekosistem di perairan. Untuk mengatasi pencemaran limbah cair etanol, digunakan metode Multi Soil Layering (MSL) sebagai salah satu metode alternatif. MSL adalah suatu metode pengolahan limbah cair yang meningkatkan fungsi tanah untuk pemurnian limbah cair. Penelitian ini menggunakan metode MSL untuk mengolah limbah cair industri etanol sebelum dibuang ke perairan. Metode MSL merupakan suatu sistem pengolahan limbah yang menggunakan beberapa material seperti tanah, zeolit, dan arang tempurung kelapa yang dibentuk dalam suatu susunan pola bata bertingkat. Faktor yang diteliti adalah kecepatan pengisian yang terdiri dari 5 tahap yaitu: 160, 320, 480, 640, dan 800L.m -2 hari -1 , kemudian ditentukan efesiensi sistem MSL dalam menurunkan kadar COD, BOD, dan TSS limbah cair industri etanol (vinass e) PSA Palimanan menggunakan kecepatan pengisian optimum. Penentuan kadar COD ditentukan dengan metode refluks, penentuan kadar BOD menggunakan metode Winkler dan penentuan kadar TSS ditentukan dengan menggunakan gravimetri. Hasil penelitian menunjukkan bahwa pengolahan limbah cair industri etanol (vinasse) PSA Palimanan dengan metode MSL dapat menurunkan kadar COD, BOD, dan TSS pada kecepatan pengisian optimum 320 L.m -2 hari -1 . Efisiensi sistem MSL dalam menurunkan kadar COD, BOD, dan TSS masing-masing sebesar 80,85%; 94,68%; dan 83,99%.

Tofu industry is one of the industries which causing pollution on the environment especially water environment. The amount of wastewater-dumped and the content of organic substances could damage the water ecosystem. Multi Soil Layering (MSL) as one of alternative method is used in order to remove the tofu industrial wastewater pollution. MSL is a method of wastewater treatment that enhances the function of soils to purify wastewater. The research aimed to determine optimum loading rate and efficiency of MSL system to remove TSS, BOD and COD. The wastewater on the MSL system is loaded at the loading rate varieties, i.e: 160, 320, 480, 640, and 800 lm -2 day -1 , and the aeration was applied for 8 a day at 1296 ld -1 . The results revealed that optimum loading rate was 320 lm -2 day -1 and efficiency of MSL system to remove TSS, BOD and COD were 78.62 % ; 98,89% and 95,53 % respectively.

Multi Soil Layering (MSL) system is a method of wastewater treatment that increase the soils function to purify wastewater. In the construction of MSL, soils mixed with the charcoal and then filled into the box of size 50x14x50 cm in layers structured like brick pattern. The aims of this research are to determine the concentration of BOD and COD on textile industrial wastewater before and after the process by MSL method. It also determines the optimal loading rate of wastewater on the MSL system, and then it can determine the efficiency of MSL system on reducing the concentration of BOD and COD on textile industrial wastewater. The method which used in this research is an experimental method. The wastewater on the MSL system is loaded on the loading rate variety: 160, 320, 480, 640, and 800 L m-2 day-1. The efficiency of MSL system to removing BOD and COD on textile industrial wastewater are determined on optimal loading rate. The research gave result that MSL method could remove BOD and COD on textile industrial wastewater on the optimal loading rate 320 L m-2 day-1. The efficiency of MSL system in removing BOD and COD on textile industrial wastewater are 96.52 and 80.87% respectively. This indicated that the method MSL serve the purpose of effective alternative method in processing of liquid waste textile industry.

A spectrophotometric method for the determination of oxalic acid has been developed, based on its catalytic effect on the redox reaction between methylene blue and sulphide, measured at the maximum absorption wavelength of 664 nm. Under the optimum conditions of 3 mL of 31 % formaldehyde; 0.8 mL of 0,067 M EDTA - Triethanolamine; 1.2 mL of 0,010 M sulphide; 2 mL of 0,0010 % methylene blue at 20 oC for 1 minute a detection limit of 0,43 mg/mL for oxalic acid determination was obtained. This method can be applied to determination of trace level of oxalic acid.

Limbah cair industri tahu memiliki nilai COD dan TSS yang tinggi, apabila dibuang ke badan perairan akan menyebabkan pencemaran lingkungan. Oleh karena itu, perlu dilakukan penurunan nilai COD dan TSS limbah cair industri tahu tersebut sebelum dibuang ke badan perairan. Penurunan nilai COD dan TSS limbah cair industri tahu dapat dilakukan menggunakan metode elektrokimia. Penelitian ini bertujuan untuk mengetahui pengaruh voltase, jarak elektroda, pH, dan waktu elektrolisis terhadap penurunan nilai COD dan TSS limbah cair industri tahu. Eksperimen dilakukan dengan mengelektrolisis limbah cair industri tahu menggunakan anoda PbO2 dan katoda Pb. Hasil penelitian menunjukkan bahwa dibawah kondisi optimum pada voltase 12V, jarak elektroda 1 cm, pH 1 dan waktu elektrolisis selama 120 menit, penurunan nilai COD dan TSS mencapai 96,33% dan 87,87%

Activated carbon from coffee dregs for TSS, BOD and COD removal of tapioca industrial wastewater has been developed. The research aimed to know the quality of activated carbon from dregs of coffee as adsorbent, consist of total rendemen, water content, ashes content and iodium adsorption; to know about the optimum contact time and optimum pH from activated carbon on reducing BOD, COD and TSS value from tapioca industrial wastewater and also to know about the decrease percentage of BOD, COD and TSS value using activated carbon from dregs of coffee. Activated carbon from dregs of coffee are activated using HCl 0,1 N and carbonization at 350°C in muffle furnace. Then, activated carbon was contacted with the tapioca industrial wastewater and used on decreasing BOD, COD and TSS value from tapioca industrial wastewater with contact time varieties 0, 10, 30, 60, 90 and 120 minutes and at pH varieties of wastewater 4, 5, 6, 7, 8, 9 and 10. The decreasing of BOD value was measured by Winkler method, decreasing of COD value measured by iodometric method and decreasing of TSS value measured by gravimetric method. The result of the research showed that the activated carbon produced characteristic consist of rendemen 14,55%; water content 3,4%; ashes content 1,88% and iodium adsorption 750,25 mg/g. It is indicated that the activated carbon that is got from dregs of coffee fulfill the criteria required by SNI No. 06-3730-1995. The result of research also showed that the activated carbon from dregs of coffee could be used for reducing the BOD, COD and TSS value in tapioca industrial wastewater at the optimum contact time of 30 minutes and pH 7. The optimum percentage of activated carbon from dregs of coffee in decreasing BOD value of tapioca industrial wastewater are 33,51%; COD value 78,96% and TSS value 61,05%.