Membrane Capacitive Deionization and Electrolysis Combination in Struvite Production

Pangestu, Aditya Kurnia Aji (2025) Membrane Capacitive Deionization and Electrolysis Combination in Struvite Production. Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

The high concentrations of ammonium and phosphate in wastewater potentially threaten water quality due to the risk of eutrophication so it should be removed and recovered as much as possible. Recently, technologies of membrane capacitive deionization (MCDI) and electrolysis have been employed for the separation and recovery of ammonium and phosphate, though typically they are used independently. This study aimed to investigate the performance of MCDI and electrolysis-magnesium anode combination for ammonium and phosphate recovery; investigate the struvite produced and its purity; and investigate the energy consumption of both processes.
Impurity ions were separated by MCDI to enhance the remaining ammonium and phosphate purity. The remaining ammonium and phosphate were fed in the electrolysis-magnesium anode experiment as a feed solution. The use of a magnesium alloy as the sacrificed anode in electrolysis provided a source of Mg for struvite formation, which reduced costs and minimized by-product formation. Artificial wastewater was used in this study.
At the initial N/P molar ratio of 1:1 with the absence of competitor ions and humic acid, MCDI removed ammonium and phosphate as much as 15.81% and 21.93%, respectively, and also reached 15.53 mg/g and 21.45 mg/g electrosorption capacity. These values were decreased 2-5 times in the presence of competitor ions such as sodium and calcium. Through a combination with electrolysis, the removal of ammonium and phosphate was increased 4-5 times to 87.32% and 63.65%, respectively. The presence of humic acid and competitor ions especially calcium affected the struvite morphology and purity. Through a combination of MCDI and electrolysis processes, the highest struvite purity was 41.80% or 0.6195 g in the Na variation. In addition, the total energy of this combination of processes consumed less amount of energy. The highest energy consumption occurred in the condition of N/P molar ratio of 10:1 without the addition of competitor ions or humic acid, which was 15.88 Wh/g precipitate.

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Konsentrasi amonium dan fosfat yang tinggi dalam air limbah berpotensi mengancam kualitas air karena risiko eutrofikasi sehingga harus dihilangkan dan dipulihkan sebanyak mungkin. Baru-baru ini, teknologi membrane capacitive deionization (MCDI) dan elektrolisis telah digunakan untuk pemisahan dan pemulihan amonium dan fosfat, meskipun biasanya digunakan secara independen. Penelitian ini bertujuan untuk menginvestigasi performa kombinasi MCDI dan elektrolisis-anoda magnesium dalam memulihkan amonium dan fosfat; untuk menginvestigasi struvite yang dihasilkan dan kemurniannya; dan untuk menginvestigasi konsumsi energi dari kedua proses.
Ion pengotor dipisahkan oleh MCDI untuk meningkatkan kemurnian amonium dan fosfat yang tersisa. Amonium dan fosfat yang tersisa diumpankan dalam percobaan elektrolisis-anoda magnesium. Penggunaan magnesium alloy sebagai anoda yang dikorbankan dalam elektrolisis menyediakan sumber Mg untuk pembentukan struvite yang mengurangi biaya dan meminimalkan pembentukan produk samping. Penelitian ini menggunakan air limbah buatan.
Pada rasio molar N/P awal 1:1 tanpa ada ion kompetitor dan asam humat, MCDI menyisihkan amonium dan fosfat masing-masing sebanyak 15,81% dan 21,93%, dan juga mencapai electrosorption capacity sebesar 15,53 mg/g dan 21,45 mg/g. Nilai ini menurun 2-5 kali dengan adanya ion kompetitor seperti natrium dan kalsium. Melalui kombinasi dengan elektrolisis, penyisihan amonium dan fosfat meningkat 4-5 kali lipat menjadi 87,32% dan 63,65%. Kehadiran asam humat dan ion kompetitor terutama kalsium mempengaruhi morfologi dan kemurnian struvite. Melalui kombinasi MCDI dan proses elektrolisis, kemurnian struvite tertinggi adalah 41,80% atau 0,6195 g dalam variasi Na. Selain itu, total energi dari kombinasi proses ini mengkonsumsi lebih sedikit energi. Konsumsi energi tertinggi terjadi pada kondisi rasio molar N/P 10:1 tanpa penambahan ion kompetitor atau asam humat, yaitu 15,88 Wh/g presipitat.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	Amonium, Elektrolisis, Fosfat, MCDI, Struvit, Ammonium, Electrolysis-magnesium anode, MCDI, Phosphate, Struvite
Subjects:	S Agriculture > S Agriculture (General) > S633.5 Fertilizers T Technology > TD Environmental technology. Sanitary engineering > TD430 Water--Purification. T Technology > TD Environmental technology. Sanitary engineering > TD455 Chemical precipitation. Coagulation. Flocculation. Water--Purification--Flocculation. T Technology > TD Environmental technology. Sanitary engineering > TD479.3 Saline water conversion T Technology > TD Environmental technology. Sanitary engineering > TD480.5 Electrodialysis
Divisions:	Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Civil Engineering > 22101-(S2) Master Thesis
Depositing User:	Aditya Kurnia Aji Pangestu
Date Deposited:	29 Jan 2025 07:03
Last Modified:	29 Jan 2025 07:03
URI:	http://repository.its.ac.id/id/eprint/117026

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