The present study pertains to batch studies on the removal of ciprofloxacin from aqueous solution using groundnut (Arachis hypogaea) shell powder and ZnO nanoparticles. An attempt has been made to compare the adsorption capacities of the two adsorbents. Nanoparticles synthesised by precipitation method have an average size of 68.61 nm as obtained from XRD and TEM data. Groundnut shell powder has been characterised by proximate and sieve analyses. Studies at varying pH 1–14, contact time, 15–180 min, and adsorbate concentration 10–100 mg/L, show maximum removal of 85.4% at pH 4 for ZnO nanoparticles and 79.6% at pH 6 for groundnut shell powder, for a contact time of 150 min and drug concentration 100 mg/L for both the adsorbents. Isotherm analyses show that favourable adsorption occurs which is physical in nature, is monolayer and there is a uniform distribution of adsorbate on the adsorbent surface. Results indicate that Freundlich, Langmuir and Temkin isotherms are obeyed. Kinetic studies indicate that pseudo-first-order kinetics is followed in both cases.

This study focuses on the removal of Mn(II) ions from aqueous solution using esterified saw dust. Most studies report single metal solutions; however, in practice the presence of only a single component in waste waters is highly unlikely. Keeping this in view, binary metal adsorption studies have been undertaken to investigate the effect of Fe(II) on the removal of Mn(II). Succinic anhydride has been used for the esterification of saw dust which has been characterised using proximate and Fourier transform infrared spectroscopy analyses. The effect of parameters such as metal ion concentration, time, pH, particle size of adsorbent and temperature on adsorption has been studied. Results obtained at optimum conditions (concentration 300 mg/L, pH 5 and time 150 min) have been subjected to isotherm analyses which show that adsorption is monolayer and physical in nature. Kinetic studies reveal that the process follows first-order kinetics, and intra-particle diffusion also occurs but it is not the rate-determining step. Thermodynamic studies indicate the adsorption process to be endothermic and spontaneous in nature. The Langmuir competitive model was applied to binary sorption to analyse the nature of competition among Mn–Fe ions, which shows that the adsorption of Mn(II) was supressed by the presence of Fe(II) ions.

Batch studies carried out at varying pH, metal concentrations, temperature, particle size, and contact times indicate 75% removal of Zn

In a quest to find efficient adsorbents for metal ions, studies on various adsorbents for metals have been of interest since the past several decades. The present study is focused on the removal of Pb (II) ions from aqueous solution using poly acrylamide grafted rice husk by batch studies. Industrial waste waters generally contain metals present as mixtures, therefore the effect of Ni (II) on the removal of Pb(II) from mixtures of Pb(II)+Ni(II) ions has also been investigated. The adsorbent has been prepared by the treatment of rice husk with acrylamide in the presence of N,N-methylene bis acrylamide and potassium persulphate. The adsorbent has been characterised by infrared spectral studies. Maximum adsorption obtained is 93% at pH 5, metal ion concentration 300mg/L in 180mins at 298K. Isotherm analyses show that both Langmuir and Freundlich isotherm models are best obeyed. The process is endothermic and spontaneous in nature and follows pseudo first order kinetics. Intraparticle diffusion also occurs but is not the rate determining step. Application of Langmuir competitive model for the binary system shows that adsorption of Pb(II) has been supressed by presence of Ni(II) ions. Studies suggest that the adsorbent is effective and can find industrial applicability.