Electronic Theses and Dissertation

Kristal violet merupakan zat warna kationik yang mempunyai sifat toksisitas tinggi, dan bersifat karsinogenik sehingga apabila tidak terdegradasi akan berdampak pada kesehatan, dapat mengiritasi kulit apabila terserap dalam jumlah tertentu. Kristal violet dapat menyebabkan komplikasi pernapasan, gagal ginjal, serta kebutaan. Tujuan dari penelitian ini adalah untuk mengetahui kapasitas penyerapan kristal violet, menganalisis kondisi optimum penyerapan kristal violet berdasarkan variabel pH, waktu kontak, massa adsorben, dan konsentrasi adsorbat serta menganalisis isoterm adsorpsi penyerapan kristal violet. Adsorben CT-Fe3O4-AH terbuat dari hasil sintesis material abu cangkang tiram, Fe3O4, dan asam humat. Adsorben CT-Fe3O4-AH memiliki kemampuan adsorpsi zat warna dikarenakan memiliki gugus hidroksil dan gugus karboksil serta bersifat magnetik. Karakteristik adsorben CT-Fe3O4-AH menggunakan SEM, XRD, dan FTIR. Hasil uji SEM menunjukkan banyak pori-pori yang terbentuk dengan luas permukaan terbesar 5,412 μm. Hasil uji XRD menunjukkan adsorben CT-Fe3O4-AH menunjukkan 3 puncak dan memiliki struktur intermediate antara struktur kristal dan amorf yang disebut turbostratik atau struktur kisi lapisan acak. Uji FTIR menunjukkan adanya gugus-gusus fungsi yang terdapat dalam adsorben CT-Fe3O4-AH yang berperang aktif dalam proses penyerapan zat warna kristal violet seperti gugus karboksil (-COOH) dan gugus hidroksil (-OH). Selain itu uji FTIR setelah proses adsorpsi menunjukkan adsorben yang mengadsorpsi kristal violet pada pada bilangan gelombang 1043.49 cm-1. Adsorben CT-Fe3O4-AH yang dihasilkan mampu menyerap kristal violet dengan kapasitas penyerapan 7,85 mg/g pada kondisi optimum yang terjadi pada pH 6 , waktu kontak 60 menit dan konsentrasi 15 mg/L. Pengujian isoterm adsorpsi dilakukan menggunakan isoterm Langmuir dan isoterm Freundlich, dan diperoleh hasil jenis isoterm yang sesuai dengan proses adsorpsi kristal violet menggunakan adsorben CT-Fe3O4-AH adalah isoterm Freundlich dengan nilai R2 yaitu 0,98592.
Kata kunci: abu cangkang tiram, SEM, XRD, FTIR, Fe3O4, asam humat, adsorpsi, kristal violet

Crystal violet is a cationic dye that has high toxicity, and is carcinogenic so that if it is not degraded it will have an impact on health, can irritate the skin if absorbed in certain amounts. Crystal violet can cause respiratory complications, kidney failure, and blindness. The purpose of this research is to determine the absorption capacity of crystal violet, analyze the optimum conditions for crystal violet absorption based on the variables of pH, contact time, adsorbent mass, and adsorbate concentration and analyze the adsorption isotherm of crystal violet absorption. CT-Fe3O4-AH adsorbent is made from synthesized oyster shell ash, Fe3O4, and humic acid. CT-Fe3O4-AH adsorbent has the ability to adsorb dyes because it has hydroxyl groups and carboxyl groups and is magnetic. Characterization of CT-Fe3O4-AH adsorbent using SEM, XRD, and FTIR. SEM test results showed many pores formed with the largest surface area of 5.412 μm. XRD test results showed CT-Fe3O4-AH adsorbent showed 3 peaks and had an intermediate structure between crystalline and amorphous structures called turbostratic or random layer lattice structure. FTIR test shows the presence of functional groups contained in CT-Fe3O4-AH adsorbent which plays an active role in the absorption process of crystal violet dye such as carboxyl group (-COOH) and hydroxyl group (-OH).n addition, FTIR test after the adsorption process showed that the adsorbent adsorbed crystal violet at wave number 1043.49 cm-1. The resulting CT-Fe3O4-AH adsorbent was able to adsorb crystal violet with an absorption capacity of 7.85 mg/g at optimum conditions that occurred at pH 6, contact time of 60 minutes and concentration of 15 mg/L. Adsorption isotherm testing was carried out using Langmuir isotherm and Freundlich isotherm, and the results obtained showed that the type of isotherm that suits the crystal violet adsorption process using CT-Fe3O4-AH adsorbent is Freundlich isotherm with R2 value of 0.98592. Keywords: oyster shell ash, SEM, XRD, FTIR, Fe3O4, humic acid, adsorption, crystal violet