Electronic Theses and Dissertation

Fitri Rukayyah (2026). Pemanfaatan Carbon Quantum Dots (CQDs) dari Limbah Kopi Robusta untuk Pembuatan Hydrogel Film Anti-UV. [Skripsi. Universitas Syiah Kuala]. Dibawah bimbingan Dr. Muhammad Nazar, S.Pd., MSCST., dan Dr. Drs. Syahrial, M. Si.

Paparan sinar ultraviolet (UV) yang berlebihan dapat berdampak buruk bagi kesehatan kulit dan menyebabkan degradasi material, sehingga memicu tingginya permintaan akan bahan pelindung UV yang ramah lingkungan. Penelitian ini bertujuan untuk pemanfaatan Carbon Quantum Dots (CQDs) dari ampas kopi robusta (Coffea canephora), dan mengintegrasikannya ke dalam matriks hidrogel polivinil alkohol (PVA) yang dibuat menggunakan asam sitrat sebagai agen pengikat silang untuk menghasilkan hidrogel film pelindung UV yang efektif. Karakterisasi meliputi analisis fluoresensi UV, spektrofotometri UV-Vis, pengukuran ketebalan, FTIR, SEM-EDS, XRD, sudut kontak, serta uji penyerapan UV dan HEBL. Hasil menunjukkan bahwa penambahan CQDs secara visual mengubah film PVA yang semula bening menjadi berwarna cokelat kekuningan. Di bawah lampu UV memancarkan fluoresensi berwarna biru. Analisis spektrofotometri UV-Vis menunjukkan penyerapan yang kuat di wilayah UV (200–400 nm). Penambahan CQDs menurunkan transmisi cahaya tampak, dengan transparansi film PVA yang semula sebesar 94,2% menurun menjadi 92,9% (PVACD01); 92,6% (PVACD05); dan 90,8% (PVACD1). Hasil uji ketebalan film berdasarkan uji ANOVA menunjukkan perbedaan nyata antara formulasi PVA dengan PVACD1, nilai opasitas meningkat menjadi 0,41%, dan kristalinitas film meningkat berdasarkan analisis XRD. Hasil analisis FTIR menunjukkan keberhasilan reaksi ikatan silang antara asam sitrat dan PVA melalui munculnya gugus ester C-O pada rentang 1248,49-1256,48 cm-1. Hasil analisis sudut kontak menunjukkan bahwa hidrogel film bersifat hidrofilik, dengan sudut kontak meningkat dari 65,7° (PVA) menjadi 80,1° (PVACD1). Dalam uji perlindungan radiasi fungsional, hidrogel film PVACD05 dan PVACD1 meningkatkan kemampuan penyerapan dengan menyerap 20-37% radiasi UV-A, 38-63% radiasi UV-B, dan 20% HEBL dibandingkan dengan PVA, yang hanya memblokir 5% UV-A, 17% UV-B, dan 3% HEBL.


Kata kunci: Carbon Quantum Dots, Ampas Kopi Robusta, Polivinil Alkohol, Hidrogel Film, Anti-UV

Fitri Rukayyah (2026). The Use of Carbon Quantum Dots (CQDs) from Robusta Coffee Waste for the Production of Anti-UV Hydrogel Films. [Skripsi. Universitas Syiah Kuala]. Dibawah bimbingan Dr. Muhammad Nazar, S.Pd., MSCST., dan Dr. Drs. Syahrial, M. Si. Excessive exposure to ultraviolet (UV) radiation can have adverse effects on skin health and cause material degradation, thereby driving high demand for environmentally friendly UV-protective materials. This study aims to utilize Carbon Quantum Dots (CQDs) derived from Robusta coffee grounds (Coffea canephora) and integrate them into a polyvinyl alcohol (PVA) hydrogel matrix prepared using citric acid as a cross-linking agent to produce an effective UV-protective hydrogel film. Characterization included UV fluorescence analysis, UV-Vis spectrophotometry, thickness measurement, FTIR, SEM-EDS, XRD, contact angle measurement, as well as UV absorption and HEBL tests. The results showed that the addition of CQDs visually transformed the originally transparent PVA film into a yellowish-brown color. Under UV light, the film emits blue fluorescence. UV-Vis spectrophotometric analysis revealed strong absorption in the UV region (200–400 nm). The addition of CQDs reduced visible light transmission, with the transparency of the PVA film decreasing from 94.2% to 92.9% (PVACD01); 92.6% (PVACD05); and 90.8% (PVACD1). Film thickness test results based on ANOVA analysis showed significant differences between the PVA formulations and PVACD1; the opacity value increased to 0.41%, and the film’s crystallinity increased based on XRD analysis. FTIR analysis results indicated the success of the cross-linking reaction between citric acid and PVA, as evidenced by the appearance of C-O ester groups in the range of 1248.49–1256.48 cm⁻¹. Contact angle analysis results showed that the hydrogel films were hydrophilic, with the contact angle increasing from 65.7° (PVA) to 80.1° (PVACD1). In functional radiation protection tests, the PVACD05 and PVACD1 hydrogel films improved absorption capacity by absorbing 20–37% of UV-A radiation, 38–63% of UV-B radiation, and 20% of HEBL, compared to PVA, which blocked only 5% of UV-A, 17% of UV-B, and 3% of HEBL. Keywords: Carbon quantum dots, Robusta coffee grounds, polyvinyl alcohol, hydrogel film, UV protection