Waste tea residue adsorption coupled with electrocoagulation for improvement of copper and nickel ions removal from simulated wastewater

Abstract

The present research involves removing copper and nickel ions from synthesized wastewater by using a simple, cheap, cost-effective, and sustainable activated green waste tea residue (AGWTR) adsorption coupled with electrocoagulation (ADS/EC) process in the presence of iron electrodes. By considering previous studies, their adsorbents used for treating their wastewaters firstly activate them by applying either chemicals or activating agents. However, our adsorbent was prepared without applying neither chemicals nor any activating agents. The operating parameters such as pH, hydraulic retention time, adsorbent dose, initial concentration, current density, and operating cost for both metals were optimized. In ADS/EC, the removal efficiency was obtained as 100% for copper and 99.99% for nickel ions. After the ADS/EC process, Fourier transform infrared (FT-IR) spectroscopy, Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS) analysis were used to characterize the adsorbent green waste tea residue. The adsorption isotherm and kinetic model results showed that the Langmuir and the pseudo-second-order were well-fitted to the experimental adsorption data better than the Freundlich and pseudo-first-order models for both Cu2+ and Ni2+ with their maximum adsorption capacity of 15.6 and 15.9 mg g−1, respectively. The above results give an option to recycle the metal-based industrial effluents, tea industry-based wastes, enabling a waste-to-green technique for adsorbing and removing the heavy metals and other pollutants in water.

Evaluation of Agrowaste Species for Removal of Heavy Metals from Synthetic Wastewater

“…Tis means that the removal efciencies were lower at the higher initial concentration values. Here, the removal efciencies of Cu, Pb, Se, Zn, and Cr ions in this process decreased as increasing the concentration from 0.5 to 10 mg/L in the frst 30 min as shown in Figures 7(a)-7(e) [10].…”

“…Te overlap of adsorbent sites as a result of adsorbent particle crowding may be the cause of this. Te percentage of metal adsorption on adsorbents is found to depend on the sorption capacity of the adsorbents within a range of starting metal concentration [10,24].…”

“…In addition, at the ideal pH, there were more negatively charged functional groups available on the biosorbent's surface for binding Cu, Pb, Se, Zn, and Cr ions. Tis resulted in a decreased struggle between protons and metal ions [10,41,42]. Te percentage of Cu, Pb, Se, Zn, and Cr ion removal was a law at pH 3.0 and 9.0 during the adsorption process because the solution was acidic [9,10], high alkaline, but at pH 6.0, the removal efciency was very high [4,9].…”

“…Tis resulted in a decreased struggle between protons and metal ions [10,41,42]. Te percentage of Cu, Pb, Se, Zn, and Cr ion removal was a law at pH 3.0 and 9.0 during the adsorption process because the solution was acidic [9,10], high alkaline, but at pH 6.0, the removal efciency was very high [4,9]. Te removal efciency of Cu, Pb, Se, Zn, and Cr ion for the case of adsorbents reached 82.2%, 93%, 81.55%, 82%, and 82% at pH � 6.0 [36], respectively.…”

“…Te long-term accumulation potential of heavy metals makes them highly harmful to humans and the human food chain. Lead, zinc, copper, chromium, selenium, and other heavy metals, for instance, have an adverse efect on environmental sources [9,10]. Aquatic bodies are being overwhelmed with microbes and waste matter.…”