DECOLOURISATION OF EMERGING TEXTILE DYES FROM AQUEOUS SOLUTION USING PNS -NANOCOMPOSITE

摘要

The objective of this work is to establish the performance of a potential adsorbent from palm-nut shell (PNS), an agricultural low-cost precursor for the removal of acidic dyes- Reactive red 195A (RR195A) and Reactive blue 160 (RB160). The modification of PNS-activated carbon was exhibited by precipitating the magnetite nanoparticles using co-precipitation method resulting in enriched PNS-nanocomposite. The structural morphology of PNS-nanocomposite were characterised by using BET surface area (BET), X-ray diffraction analysis (XRD), Raman spectroscopy (RS), VSM data, High Resolution TEM (TEM) with SAED pattern. TEM pictures showed that the prepared nanocomposite was in pseudo-ball shaped. The microporous and mesoporous pore structures of the adsorbent were known to be obtained by t-plot and BJH respectively. The low retentive force value and saturation magnetisation (0.84 emu) value justify the magnetic separation from the aqueous solution. The best fit of pseudo-second order kinetics model with the high coefficient value better describe the process of adsorption of Reactive red 195A and Reactive blue 160 onto the adsorbent. The monolayer Langmuir isotherm (23.8 mg/g – RR195A & 62.5 mg/g – RB160) pictured the better fit. Thermodynamic parameter values (ΔS1, ΔH1, ΔG1) confirm the dependency of temperature by the adsorption reaction process between adsorbent and adsorbate and their spontaneous and endothermic nature was also justified. The result of this work will be useful for future studies in the degradation of azo dyes using affordable precursor PNS. These studies confirm the eligibility of the adsorbents indicating their valuable application such as high adsorption capacity, excellent separation nature in the field of adsorption process for the clean-up of wastewater.