Tempe production will produce tempe liquid waste which has a high nutrient content that increasing the value of chemical oxygen demand (COD) in water. This will increase the value of water pollution if the tempe liquid waste is disposed directly into the environment. According to the regulation of the Ministry of Environment 2014, COD values should not exceed 150 mg / L. However, in some cases, Kampung Sanan, for example, has a COD value of 3,782 mg / L. This indicates the high level of pollution caused by tempe liquid waste.
Based on these problems, students of the Faculty of Mathematics and Natural Sciences (FMIPA) Universitas Brawijaya made an innovation to reduce the amount of tempe waste in the water environment by making a photocatalyst from iron sand and volcanic ash in the form of beads whose performance is assisted by light. They are Pandan Sari Intan Cahyani (Chemistry 2017), Asnaili Alfi Nurillah (Chemistry 2017), and Aditiya Anggraeni (Chemistry 2018).
The team leader, Pandan Sari Intan Cahyani explained, Photocatalyst is a chemical material obtained from the combination of semi-conductor and carrier materials. And iron sand was chosen since it is rich in iron oxide. Iron oxide is a semiconductor material that can capture light optimally to help decompose the waste.
Meanwhile, the selection of volcanic ash is also based on the amount of silica content. Silica is an absorbent material with wide pores that can improve photocatalyst performance and also absorption.
“Silica in this case functions as a carrier, so that the two materials will be combined or impregnated to decompose the waste optimally,” explained Pandan.
In this study, the photocatalyst was formed into beads. The shape of the beads will give a different shape to the waste.
“Having a granular shape will make it easier to separate from the waste so that the photocatalyst can be reused. Besides the ease of use, the shape of the beads can also improve the performance of the photocatalyst because more of the active side of iron oxide is exposed to light, “he explained.
The use of iron sand and volcanic ash for photocatalysts is because these materials are very abundant around us, cheap, non-toxic, and the manufacturing process is relatively easy and does not cause other environmental problems.
“Hopefully in the future, I hope this research can provide a solution to overcome water pollution without causing other environmental problems,” said Pandan.
With this research, they win to get funding in the Student Creativity Program (PKM) 2020 held by the Directorate of Learning and Student Affairs, Ministry of Education and Culture. [PKM Team/ Humas UB / Trans. Iir]
