SINTESIS NANOFIBER POLIVINIL ALKOHOL /KITOSAN DAN POLIVINIL ALKOHOL/KITOSAN/SiO2 SEBAGAI ADSORBEN [AuCl4]-

ATIKA SALMA, Prof. Drs. Sri Juari Santosa, M.Eng, Ph.D; Dr.rer.nat.Nurul Hidayat Aprilita

2018 | Tesis | MAGISTER KIMIA

Nanofiber polivinil alkohol/kitosan dan polivinil alkohol/kitosan/SiO2 sebagai adsorben [AuCl4]- telah berhasil disintesis. Nanofiber disintesis melalui metode electrospinning menggunakan perbandingan volume PVA:Kitosan (8:1) dan penambahan SiO2 0,2 gram. Nanofiber dikarakterisasi menggunakan SEM, FTIR dan XRD. Parameter pengujian terhadap kemampuan adsorpsi nanofiber meliputi variasi pH, waktu kontak, variasi konsentrasi, kinetika adsorpsi dan isoterm adsorpsi. Analisis SEM, FTIR dan XRD untuk mengetahui morfologi permukaan, gugus fungsional serta puncak difraksi nanofiber. Data SEM menunjukkan bahwa nanofiber PVA/Kitosan dan PVA/Kitosan/SiO2 telah berhasil disintesis berdasarkan terbentuknya ukuran serat seragam pada perbesaran 25000 kali. Data spektra FTIR menunjukkan vibrasi tekuk pada daerah 1651 cm-1 yang mengindikasikan keberadaan gugus amina vibrasi pada 1095 cm-1 merupakan vibrasi ulur siloksan. Data XRD nanofiber PVA/Kitosan dan PVA/Kitosan/SiO2setelah adsorpsi menunjukkan adanya puncak difraksi pada 2 theta = 19,9 (kitosan); 2 theta = 29,12 (SiO2); 2 theta = 38,21; 42,97 dan 64,49 (Au). Adsorpsi optimum ion [AuCl4]- oleh nanofiber PVA/Kitosan dan PVA/Kitosan/SiO2 terjadi pada pH 6, waktu optimum masing-masing 50 menit dan 40 menit serta konsentrasi optimum pada 40 mg L-1. Adsorpsi [AuCl4]-pada nanofiber PVA/Kitosan dan PVA/Kitosan/SiO2 mengikuti isoterm Freundlich, dengan kapasitas adsorpsi maksimum masing-masing 0,072 dan 4,539 mg g-1, konstanta Freundlich (n) 0,54 dan 1,67; koefisien korelasi R2 0,939 dan 0,937. Kinetika adsorpsi mengikuti orde kedua semu (Ho dan McKay) dengan laju adsorpsi untuk nanofiber PVA/Kitosan dan PVA/Kitosan/SiO2 berturut-turut 5,4 x10-4 dan 1,0 x 10-4 g mg-1 menit-1.

Polyvinyl alcohol/chitosan and polyvinyl alcohol/chitosan/SiO2 nanofibers for the adsorbent of [AuCl4]- have been made. Nanofiber have been obtained by electrospinning method using volume ratio of PVA:chitosan (8:1) and 0.2 gram of SiO2. The nanofibers then characterized by SEM, FTIR and XRD. Several parameters examined in this study, includes:variation of pH, contact time, variation of concentration, adsorption kinetics and adsorption isotherms. The SEM, FTIR and XRD data showed the topograph of nanofibers surface, functional groups and diffraction peak of nanofibers. SEM results showed that the nanofibers have been successfully synthesized based on formation of the same fiber size with magnification 25000 times. FTIR spectra showed the bending vibration of nanofibers at 1651 cm-1, which indicated the existence of amine, stretching vibration at 1095 cm-1 was siloxane functional group. XRD analysis showed that diffraction peak at 2 theta = 19.9 (chitosan); 2 theta = 29.12 (SiO2); 2 theta = 38.21; 42.97 and 64.49 (Au). PVA/chitosan and PVA/chitosan/SiO2 nanofibers displayed optimum adsorption for [AuCl4]- at pH 6, optimum time at 50 and 40 minutes, respectively; the optimum concentration at 40 mg L-1. Adsorption of [AuCl4]- by PVA/chitosan and PVA/chitosan/SiO2 followed Freundlich isotherm, with optimum adsorption capacity 0.072 and 4.539 mg g-1, Freundlich constant (n) counted 0.54 and 1.67; coefficient correlation (R2) counted 0.939 and 0.937, respectively. Kinetics adsorption followed pseudo second order by Ho and McKay, the adsorption rate of PVA/chitosan and PVA/chitosan/SiO2 nanofibers counted 5.4 x 10-4 and 1.0 x 10-4 g mg-1 minutes-1, respectively.

Kata Kunci : Kata kunci:nanofiber, isotermFreundlich, adsorpsi, [AuCl4]-.