REMAZOL RED DYE REMOVAL IN WATER SOLUTIONS USING A MIXED ADSORVENT COMPOSED OF ASPERGILLUS NIGER AND ELEPHANT GRASS

O descarte de efluentes têxteis não tratados nos meios aquosos pode ocasionar em um rápido esgotamento do oxigênio dissolvido, o que resulta em um desequilíbrio noecossistema. São vários os métodos utilizados na remoção de cor, e, dentre eles, a adsorção vem se mostrando como um método de tratamento simples, barato e eficiente. O objetivo deste trabalho consiste em avaliar a habilidade da biomassa mista de Aspergillus niger e capim elefante (Penissetum purpureum Schum) na remoção do corante Remazol Vermelho de uma solução aquosa sintética sob difrentes condições de temperatura (30, 40 e 50 °C), concentrações variando entre 25 e 105 mg/L, tempo de adsorção de 0 a 200 minutos e pH 2.0. O estudo cinético foi caracterizado pelo modelo de pseudo-segunda ordem. Já o modelo de Langmuir se mostrou o melhor ajuste linear das isotermas de adsorção, apresentando uma capacidade de adsorção de 3,42 mg g-1. A esponteneidade da reação de adsorção foi avaliada através daenergia lvire de Gibbs. O estudo termodinâmico indicou que a adsorção é favorável e espontânea, além de que o aumento da temperatura ocasiona em uma redução na capacidade de adsorção. Estes resultados obtidos em efluentes sintéticosdemonstram que o adsorvente misto produzido neste estudo é uma alternativa promissora no tratamento de efluentes contaminados com Remazol Vermelho.

Removal of textile azo dyes with mixed biomass of Aspergillus niger and orange peel (Citrus sinensis L. Osbeck)

This study evaluates the removal of textile dyes using mixed adsorbents prepared by the growth of Aspergillus niger in orange peels. The highest azo dye removal efficiency was obtained at pH 2, solid: liquid ratio (1: 4 g·mL-1) and time of equilibrium of 250 minutes for each dye. The concentrations of Remazol Black B (RB) and Remazol Red (RR) in both synthetic textile effluents were between 25 mg·L-1 and 100 mg·L-1. The mixed adsorbent was characterized by X-ray diffraction (XRD), spectroscopy infrared region (FTIR) and scanning electron microscopy (SEM). The results indicated that there was a 100% removal of RB and 94.85% of RR at the concentration of 25 mg·L-1. At the concentration of 100 mg·L-1, the percentages of removal reached 98.87% for RB and 96.37% for RR, respectively. The proposed mixed adsorbent was able to remove the textile dyes, presenting adsorptive capacities of 20.77 mg·g-1 and 19.28 mg·g-1 for the dyes RB and RR. Regarding the adsorption kinetics, the experimental data showed that the pseudo second order model was the one that best explained the adsorptive process. For the equilibrium results, the Langmuir model and the Langmuir-Freundlich model were the ones that best fit the experimental data of RB and RR, respectively. The mixed adsorbent produced is a promising alternative for the treatment of textile effluents.

Perbandingan Aktivitas Reaksi Fotodegradasi Remazol Red dengan TiO2 Anatas 50%-Rutil 50% dan TiO2 Anatas Tersupport AgI

Kandungan ikatan azo dalam zat pewarna tekstil remazol red mengakibatkan zat warna lebih mudah larut dalam air dan memiliki stabilitas yang tinggi. Hal ini menyebabkan limbah tekstil memerlukan penanganan khusus agar aman dan tidak memberikan dampak negatif ketika dilepas ke perairan. Salah satu cara alternatif untuk menangani limbah non-degradable adalah dengan menggunakan metode fotodegradasi dengan bantuan fotokatalis. Penelitian ini bertujuan untuk membandingkan aktivitas reaksi fotodegradasi remazol red dengan fotokatalis TiO2 anatas 50%-rutil 50% dan TiO2 anatas tersupport AgI. Proses fotodegradasi Remazol red dilakukan dengan memvariasi fotokatalis yang digunakan yaitu fotokatalisis TiO2 anatas 50%-rutil 50% dan TiO2 anatas tersupport AgI dan lama waktu penyinaran yaitu 15 menit, 30 menit, 45 menit, 60 menit, 75 menit, dan 90 menit. Untuk mengetahui pengaruh lama penyinaran terhadap fotodegradasi Remazol red, maka dilakukan pengukuran absorbansi larutan menggunakan spectronic 200 pada panjang gelombang 558nm setiap selang waktu 15 menit. Hasil aktivitas fotokatalitis menunjukkan persentase degradasi remazol red pada sistem TiO2 anatas tersupport AgI, TiO2 anatas 50%-rutil 50% dan tanpa katalis berturut-turut sebesar 32%, 16%, dan 7%. Oleh karena itu fotokatalis TiO2 anatas tersupport AgI memiliki aktivitas fotokatalisis yang lebih baik daripada fotokatalis TiO2 anatas 50% - rutil 50%

Three-Dimensional Hierarchical Porous TiO2 for Enhanced Adsorption and Photocatalytic Degradation of Remazol Dye

Three-dimensional hierarchical mesoporous structures of titanium dioxide (3D-HPT) were synthesized by self-assembly emulsion polymerization. Polymethyl methacrylate (PMMA) and pluronic 123 (P123) were used as the soft templates and co-templates for assisting the formation of hierarchical 3D porous structures. The TiO2 crystal structure, morphology, and Remazol red dye degradation were investigated. The 3D-HPT and normal three-dimensional titanium dioxide (3D-T) presented the good connection of the nanoparticle-linked honeycomb within the form of anatase. The 3D-HPT structure showed greatly enhanced adsorption of Remazol dye, and facilitated the efficient photocatalytic breakdown of the dye. Surprisingly, 3D-HPT can adsorb approximately 40% of 24 ppm Remazol dye in the dark, which is superior to 3D-T and the commercial anatase at the same condition (approx. 5%). Moreover, 3D-HPT can completely decolorize Remazol dye within just 20 min, which is more than three folds faster than the commercial anatase, making it one of the most active photocatalysts that have been reported for degradation of Remazol dye. The superior photocatalytic performance is attributed to the higher specific surface area, amplified light-harvesting efficiency, and enhanced adsorption capacity into the hierarchical 3D inverse opal structure compared to the commercial anatase TiO2.

Synthesis and Characterization of Porous Magnetite Nanosphere Iron Oxide as a Novel Adsorbent of Anionic Dyes Removal from Aqueous Solution

Porous magnetite Fe3O4 nanospheres (PMNs) are synthesized for removal from an aqueous solution of anionic dyes Acid Red 57 (AR57) and Remazol Red (RR) and are used as a high-performance adsorbent. Characterization of PMNs was carried out using various techniques, such as Fourier-transform infrared spectroscopy, the surface area measured by Brunauer Emmett-Teller (BET), and it was found 143.65m2g-1, and were spherical-shaped as determined by TEM. Surface modification was calculated using electron microscopy (SEM) scanning. The spherical morphology of the PMNs is very uniform, with an average particle size of ~25,84 nm in diameter. Variables such as initial pH, the dosage of adsorbent, contact time, and temperature were analyzed to find the optimal adsorption conditions for extracting Acid Red 57 (AR57) and Remazol Red (RR) from aqueous solutions. For respective AR57 and RR, the optimal pH for the extraction of the anionic dyes examined from water solutions was 3 and 4. The maximum adsorption potential expected for AR57 and RR dyes was 888.68 and 808.43 mgg−1, respectively. The effects of the initial solution pH, temperature, initial concentration, contact time, salinity, and dosing of PMNs were systematically analyzed. These dyes were suitable for acid pH adsorption, as the PMNs Zero-charge point (pHPZC) equals 4.3. Adsorption findings were based on the Langmuir, Freundlich, Dubinin – Radushkevich, and Temkin adsorption isotherms. The adsorption isotherm had been found to follow the Langmuir model for both dyes. The mean adsorption energy (Ea) is 20.24 and 31.3 kJmol−1 for AR57 and RR, respectively, indicating a chemisorption process. The adsorption kinetics had been found to follow the pseudo-second-order kinetic model. The adsorption process was verified to be endothermic and spontaneous by thermodynamic studies. Using ethanol as a solvent, it was also studied the process of desorption of the adsorbed anionic dyes.