Fresh milk production in East Java ranks first in national milk production and reaches more than five hundred thousand tons (Central Statistics Agency, 2019).

In line with the high milk production, it is important to diversify dairy products to convert excess amounts of fresh milk.

One example of a dairy product is kefir. Kefir is produced by fermentation technology using kefir grains which contain lactic acid and yeast bacteria.

Kefir has two main components; curd and whey. Curd contains complex proteins, so it tends to be non-polar like oil. Meanwhile, whey contains a lot of water, so it tends to be polar.

These two components have their own functions. Curd is used as an ingredient in cosmetics and beauty masks, while whey is used as an ingredient in nutritious drinks. Therefore, these two components are often be separated.

The separation method used by the community is usually by using an ordinary filter cloth so it tends to produce products that have low purity.

This separation process usually takes a relatively long time (up to 24 hours). Bu in the mean time, it may cause the product to be contaminated by other microorganisms. In some cases, the resulting product sometimes has a bad smell.

Moving on from these problems, three Chemical Engineering students tried this kefir separation application using a silica-based superhydrophobic membrane.

The three of them are Mohammad Fahmi Fathikhul Umam, Muhammad Rifaldi, and Herlinda Novianti under the guidance of Ir. Bambang Poerwadi M.S.

Separation technology using membranes is preferred, because it has high selectivity and is energy efficient.

The membrane used is a superhydrophobic membrane that has a contact angle above 150º, means that the membrane has the ability to reject polar components (such as water) and pass non-polar components (such as oil).

The concept of separation using a superhydrophobic membrane is based on differences in polarity.

Non polar curd will escape from the membrane, while polar whey will be ejected from the membrane.

“Silica-based membranes in terms of raw materials are very beneficial, because silica can be found in various sources. Among them are sea sand, rice husks, bagasse ash, and hot mud,” said one of the team member, Muhammad Rifaldi.

This research, which received DIKTI funding through PKM, was conducted for two months. The data used in the study used online data collection because of the COVID-19 pandemic conditions. (mfu/mic)