SYNTHESIS OF ACTIVATED CARBON AND CMC BEADS FROM CORN HUSK FOR EFFLUENT TREATMENT

Adsorption of dyes from the effluent is a well-known and feasible method been used in the industry. In the present work we are using corn husk agricultural waste as a sustainable raw material for synthesizing activated carbon using biopolymer carboxyl methyl cellulose for formation of beads. The beads formed are been used for removal of reactive ultra-orange RGB , acid telon yellow FG 01, basic coracryl red C2B. The surface area of beads is 39.87m2 /g. The maximum adsorption of reactive orange RGB , acid telon yellow and basic coracryl red is 68.25mg/g, 72.54mg/g and 30.21mg/g for 50ml of dye solution. The stock solution 0.4g/l of dye solution was prepared for each dye respectively. The beads formed shows a variable pH from 2 to 12 which is favourable for textile effluent. This is a green approach to use the agricultural waste for waste water treatment.

Application of Cationic Surfactant Modified Mengkuang Leaves (Pandanus atrocapus) for the Removal of Reactive Orange 16 from Batik Wastewater: A Column Study

The feasibility of Mengkuang leaves (Pandanus atrocarpus) as a non-conventional low-cost adsorbent for the removal of an anionic dye, Reactive Orange 16 (RO16), was investigated. Among the dyes that have been commonly used in the Batik industry was reactive dye. In this study, Mengkuang leaves were chemically modified with cetyltrimethylammonium bromide (CTAB), a cationic surfactant, to improve their adsorption performance toward anionic dyes. The adsorbent’s morphological characteristics were analyzed using a scanning electron microscope (SEM). The surface of modified Mengkuang leaves seems to be irregular and uneven, with more porous structures than raw Mengkuang leaves. Adsorption of RO16 dye in fixed bed column using modified Mengkuang leaves adsorbent indicated the breakthrough time increased at higher bed height and lower flow rate. The breakthrough times for bed height of 0.5, 2, and 4 cm were at 16, 68, and 165 min, respectively. Meanwhile, breakthrough time for the flow rate of 2,5 and 7 mL.min-1 were at 327, 104, and 43 min, respectively. However, the study utilizing raw Mengkuang leaves showed no significant removal of RO16. Thus, it can be concluded that the cationic surfactant modification of Mengkuang leaves is advantageous for anionic dye removal. This anionic dye removal is significantly influenced by column parameters such as bed height and flow rate as the plotted breakthrough curves obtained from experimental data were similar to the typical breakthrough curve. When applied to the Yoon-Nelson model, the adsorption data provided the best fit with the R2 value above 0.95. The time taken for the breakthrough is very similar to model prediction values. Experiments with real batik dye wastewater showed the immense potential of modified Mengkuang leaves where total removal of real Batik wastewater was instantaneous.

A DFT Analysis of Electronic, Reactivity, and NLO responses of a Reactive Orange Dye: the Role of Hartree-fock Exchange Corrections

An experimental and theoretical study based on DFT/TD-DFT approximations is presented to understand the nature of electronic excitations, reactivity, and NLO properties of reactive orange 16 dye (RO16), an azo chromophore widely used in textile and pharmacological industries. The results show that the solvent has a considerable influence on the electronic properties of the material. According to experimental results, the absorption spectrum is noticed by four intense transitions, which have been identified as $\pi\rightarrow\pi^*$ states using TD-DFT calculations. However, the TD-DFT results reveal a weak $n\rightarrow\pi^*$ in the low-lying spectral region. Continuum models of solvation indicate that these states suffer bathochromic and hypsochromic shifts, respectively. However, the expected blue shift for the absorption $n\rightarrow\pi^*$ is only described using long-range or dispersion-corrected DFT methods. RO16 is classified as a strong electrophilic system ($\omega > 1.5$ eV). From vacuum to solvent, the environment is active and changes the nucleophilic status from strong to moderate nucleophile ($2.0 \leq N \leq 3.0$ eV). The results also suggest that all electrical constants are strongly dependent on long-rang and Hartree-Fock exchange contributions, and the absence of these interactions gives results far from reality. In particular, the results for the NLO response show that the chromophore presents a potential application in this field, with a low refractive index, and first-hyperpolarizability ca. 214 times bigger than the value usually reported for urea ($\beta = 0.34 \times 10^{-30}$ esu), which is a standard NLO material. Concerning the solvent effects, the results indicate that $\beta_\textrm{total}$ increases ca. 180\% regarding the gas-phase value. The results suggest RO16 is a potential compound in NLO applications.

Adsorption, Equilibrium Isotherm, and Thermodynamic Studies towards the Removal of Reactive Orange 16 Dye Using Cu(I)-Polyaninile Composite

To overcome some of the limitations of activated carbon like efficiency, cost-effectiveness, and reusability, the present work deals with Cu(I)-based polyaniline (PANI) composite for the removal of reactive orange 16 (RO16) dye. Following the synthesis and characterization of formed Cu(I)-PANI composite, the batch experiments performed for the removal of RO16 dye indicated that the composite has the capacity to reduce the coloring from RO16. The experiments were conducted for the study of effects against changes in pH, time, and dose at room temperature, where we observed for a pH impact on the dye adsorption capacity in the range of 2–12. Among all, the optimal RO16 removal was found to be 94.77% at a pH of 4 and in addition, the adsorption kinetics confirmed to be pseudo-second-order with more suitability towards the Langmuir isotherm, where it is presumed to be the formation of a monolayer of dye molecule at the homogeneous absorbent surface. The calculated maximum capacity, qm, determined from the Langmuir model was 392.156 mg/g. Further application of isotherms to attain thermodynamic parameters, a slight positive value of S° for RO16 adsorption was observed, meaning that there is an increased randomness in the irregular pattern at the specific Cu(I)-PANI interface for an adsorption process. This mechanism plays an essential role in maintaining the effects of water pollution; and, based on the analysis therefore, it is prominent that the Cu(I)-PANI composite can be employed as a promising and economical adsorbent for the treatment of RO16 and other dye molecules from the sewage in wastewater.

Removal of reactive orange 16 with nZVI-activated carbon/Ni: optimization by Box-Behnken design and performance prediction using artificial neural networks

Purpose The purpose of this paper is to analyze nano zero-valent iron (nZVI)-activated carbon/Nickel (nZVI-AC/Ni) by a novel method. The synthesized adsorbent was used to degrade reactive orange 16 (RO 16) azo dye. Design/methodology/approach The optimum conditions for the highest removal of RO 16 dye were determined. Characterization of nZVI-AC/Ni was done by scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction and energy-dispersive X-ray spectroscopy. The nZVI-AC/Ni were used for the removal of dye RO 16 and the parameters affecting were discussed such as pH, adsorbent dosage, contact time and concentration of dye. To investigate the variables and interaction between them, an analysis of variance test was performed. Findings The characterization results show that the synthesis of nZVI-AC/Ni caused no aggregation of nanoparticles. The maximum dye removal efficiency of 99.45% occurred at pH 4, the adsorbent dosage = 0.1 gL-1 and the dye concentration of 10 mgL-1. Among various algorithms of feed-forward backpropagation neural network, Levenberg–Marquardt with mean square error (MSE) = 9.86 × 10–22 in layer = 5 and the number of neurons = 9 was selected as the best algorithm. On the other hand, the MSE of the radial basis function model was 0.2159 indicating the good ability of the model to predict the percentage of dye removal. Originality/value There are two main innovations. One is that the novel nZVI-AC/Ni was prepared successfully. The other is that the optimized conditions were obtained for the removal of RO 16 dye from an aqueous solution. Furthermore, to the best of the knowledge, no study has ever investigated the removal of RO 16 by nZVI-AC/Ni produced.