In the present study, removal efficiency (%) of Rubus ellipticus leaves (REL) as an adsorbent for the removal of Pb(II), Cu(II) and Cd(II) ions was investigated. Different parameters i.e., pH, contact time, temperature, adsorbent dose and initial metal ion concentration were investigated to obtain the optimum adsorption efficiency. At pH 4, a maximum adsorption was 84.6, 80.2 and 74.5 % for Pb(II), Cu(II) and Cd(II) ions, respectively. The maximum adsorption of all the three metal ions obtained at contact time (75 min), initial metal ion concentration (10 mg/L), temperature (25 ºC) and adsorbent dose (5.0 g). The equilibrium adsorption of Pb(II), Cu(II) and Cd(II) ions at different temperature was described by Langmuir, Freundlich and Temkin isotherms. The equilibrium data fitted well the Langmuir adsorption isotherm. Thermodynamic parameters like Gibb′s free energy (ΔGº), enthalpy (ΔHº) and entropy (ΔSº) were also calculated. The calculated parameters indicated that adsorption of Pb(II), Cu(II) and Cd(II) ions onto Rubus ellipticus leaves (REL) was spontaneous (ΔGº < 0), endothermic (ΔGº > 0). The feasibility of the process was evident from the positive value of ΔSº.

Heavy metals cause outrageous ecological risks when released into the environment from many point and non-point sources. Biosorbents prepared from the leaves of Eupatorium adenophorum (AEA) and Acer oblongum (AAO) were used as practical solutions to remove the toxic heavy metal cadmium (Cd2+) from wastewater. Biosorption of Cd2+ was investigated using AEA and AAO biomass under batch conditions. The effect of operating variables like temperature, contact time, the pH impact, and initial metal concentration and biosorbent portion on Cd2+ removal has been studied. The optimal pH and the sorbent dosage were found to be 7.0 and 2.0 g L−1, respectively, and removal efficiency attained was 93.3% with an equilibrium removal time of 90 min. The equilibrium uptake of Cd2+ was evaluated by Freundlich, Langmuir, and Temkin isotherm models. The Langmuir isotherm model was proved fit confirming single layer of sorption. The biosorption of Cd2+ onto activated AEA and AAO biomass achieved were 45.45 mg g−1 and 44.64 mg g−1 respectively. The adsorption affinity of AEA toward Cd2+ was discovered a lot more prominent than AAO biomass. The kinetic data of Cd2+ biosorption onto activated AEA and AAO, fitted with a pseudo-second-order well with higher values of R2 (> 0.99). Thermodynamics disclosed that the adsorption process was spontaneous (∆G0 < 0), endothermic (∆H0 > 0), and feasible (ΔS0 > 0). The adsorption of Cd2+ onto AEA was more exothermic and spontaneous than the AAO biosorbent. Additionally, FT-IR and SEM analysis uncovered that Cd2+ were adsorbed onto selected biomassdue to –NH–, –COOH, –OH, and –NH2 groups. Ionic, coordination bond formation, and electrostatic interaction with Cd2+ demonstrated that they were promising biosorbent for wastewater treatment.

In present study, Pyras pashia leaves were used as low cost biosorbent to study biosorption of Cu(II), Pb(II) and Cd(II) ions from contaminated wastewater. In the employed batch methods pH, contact time, metal ion concentration, temperature, biosorbent doses were taken as study parameters. The pH was varied from pH 1-9 to study the influence of pH on biosorption of metal ions by Pyras pashia. The optimum pH for the removal of Cu(II), Pb(II) and Cd(II) is observed at pH 5. The biosorption equilibrium time was varied between 15-75 min. Langmuir, Freundlich and Temkin isotherms were employed to study the biosorption. The biosorption parameter fits well with Langmuir isotherm. The biosorption of metal ions was increased with increasing biosorbent dose and contact time while increase in pH, metal ion concentration and temperature decrease the biosorption. Thermodynamic data suggest that the bisorption process was spontaneous, feasible and endothermic.

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