Melia azedarach Activated Carbon and its novel TiO2 Nanocomposite for Chemisorption and Photodecoloration of Reactive Orange 16: Isotherm and Kinetic Modeling

Abstract

Background: Bulk generated textile wastewater loaded with dyes is posing stern threat to aquatic health especially when dumped without prior treatment. Lignocellulosic waste based activated carbon (AC) and Titania (TiO2) suspension can constitute the emerging technological solution. Objectives: Best lignocellulosic precursor biomass, Melia azedarach (Darek sawdust – DSD), was selected for orthophosphoric acid impregnated AC production and novel AC-DSD-TiO2 nanocomposite was developed. AC-DSD and ACDSD-TiO2 nanocomposite were employed for reactive orange 16 (RO16) dye adsorption in batch and decoloration in photocatalytic reactors respectively. Methods: Materials were characterized by Scanning electron microscope (SEM), energy dispersion X-ray (EDX) spectroscopy and Fourier transform infrared spectroscopy (FTIR). For AC-DSD production, the raw powdered biomass of DSD was impregnated (value = 2) with H3PO4 at room temperature and after shaking, was placed in a muffle furnace at 100 °C for 12 h in glass tubes and subsequently carbonized at high temperature of 400 °C for 30 min. Batch reactor parameters for AC-DSD-RO16 system were optimized as a function of contact time, adsorbent dose, temperature, initial dye concentration and pH. For AC-DSD-TiO2 nanocomposite synthesis, AC-DSD and TiO2 paste dried in furnace at 90 °C and calcined at 300 °C and stored in desiccator. Results: AC-DSD exhibited RO16 adsorption capacity of 92.84 mg/g. The experimental data were best described by Langmuir and Dubinin-Radushkevich isotherms with high R2 of 0.9995 and 0.9895 and closeness of predicted adsorption capacities of 94.15 and 88.58 mg/g respectively. This determines chemisorption nature for RO16 adsorption onto ACDSD. The experimental data was well explained by pseudo-second order kinetic model. Thermodynamic parameters also suggest the endothermic, chemisorption and spontaneous adsorption reaction. Photocatalytic studies of novel AC-DSDTiO2 revealed the higher Kc = 0.1833 value over Kad= 0.0572. Conclusions: Melia azedarach AC-DSD and its novel AC-DSD-TiO2 nanocomposite proves that these materials could provide an optimal solution for treating textile dye solutions as effective the good adsorbent and photocatalyst.

Visible Light-Induced Reactive Yellow 145 Discoloration: Structural and Photocatalytic Studies of Graphene Quantum Dot-Incorporated TiO2

“…These results are contrary to the usual observation that increasing the active sites through increasing the nanocomposite contents should increase nanocomposite efficiency, however, as a heterogeneous photocatalytic reaction depends on the availability of photons, and increasing the nanocomposite dose causes the reaction solution to become turbid, which prevents the photons from reaching the nanocomposite surface and reduces the efficiency of the nanocomposite. Similar findings are reported in previous heterogeneous photocatalytic studies. − The rest of the study was conducted using an optimum dose of 1 mg mL –1 .…”

“…Similar findings are reported in previous heterogeneous photocatalytic studies. 35 − 37 The rest of the study was conducted using an optimum dose of 1 mg mL –1 .…”

Fe-TiO2/AC and Co-TiO2/AC Composites: Novel Photocatalysts Prepared from Waste Streams for the Efficient Removal and Photocatalytic Degradation of Cibacron Yellow F-4G Dye

“…The best adapted isotherm models and the adsorption capacity of some different dyes in various TiO 2 /AC adsorbents in aqueous solutions have been investigated by other researchers and these results are summarized in Table 1. The adsorption isotherm study of composites in this research demonstrated similar trends to those reported in the literature [9,[86][87][88]. It also reveals that Fe-TiO 2 /AC or Co-TiO 2 /AC composites could be used as a potential adsorbent for dye removal, despite the decrease of adsorption capacity by increasing the doping percentage, high adsorption capacity values are still obtained in comparison to other studied composites, as displayed in Table 1.…”

“…The best adapted isotherm models and the adsorption capacity of some different dyes in various TiO2/AC adsorbents in aqueous solutions have been investigated by other researchers and these results are summarized in Table 1. The adsorption isotherm study of composites in this research demonstrated similar trends to those reported in the literature [9,[86][87][88]. The generated values by the Langmuir model correspond with the plateau of the experimental data observed in Figure 4, and the comparison of R 2 and RMSE between all the models suggests that the Langmuir model was the most suitable model to fit the data.…”

Removal of color and COD from textile dyeing effluent by adsorption technique using montmorillonite clay

“…The textile industry is a major consumer of water, dyes, and other chemicals required in various phases of fabric production. If not properly treated, a significant proportion of effluents including spent or unutilized dyes are likely to be deposited in the freshwater ecosystem (Khan et al., 2020; Shah et al., 2021). Textile dyes are organic substances that are either natural or synthetic and are used to color fabrics.…”