Department of Chemical Engineering

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Author: search.filters.author.Maheshwari, UtkarshSubject: search.filters.subject.Adsorption

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Now showing 1 - 4 of 4
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    Application of Nanomaterials for the Removal of Pollutants from Effluent Streams
    (Bentham Science, 2012) Gupta, Suresh; Maheshwari, Utkarsh
    Rapid industrialization with the increase in the population leads to the water crisis. The number of industries using heavy metals such as copper, chromium, nickel, zinc, etc. in their process is also leaving behind the effluent containing a large amount of heavy metals which discharged directly to the water bodies. There are constraints set by the regulatory bodies of government on the industries to maintain an upper level discharge limit for each of the metal ion. There are various methods available for the removal of metal ions which are selected according to the requirement. Adsorption is one of the optimal solutions for the removal of metal ions from industrial effluent streams. It is helpful in reducing the operational cost and size of equipment along with the increase recovery of metal ions. Adsorption is a surface phenomenon so the foremost property required for a perfect adsorbent is the higher surface area. Nanoparticles are now being preferred to be used as an adsorbent due to their large surface area which is a very important characteristic for a desired adsorbent. Development of nanoparticles has been the subject of enormous interest since the past decade. They have incredible adsorption properties due to the presence of high-energy adsorption sites and they also have excellent binding energies or interaction potentials for physisorption than traditional adsorbents. This study summarized the use of nanomaterial for the removal of metal ions from wastewater streams. It also highlights the various types of nanomaterials, their fabrication method and characteristics. The mechanism of metal adsorption onto various nanomaterials is also described in this study.
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    A novel method to identify optimized parametric values for adsorption of heavy metals from waste water
    (Elsiever, 2016-02) Gupta, Suresh; Maheshwari, Utkarsh
    In the present study, a strategy to obtain the optimum parameters for the removal of metal ions from wastewater is developed. A generalized model is proposed which can be used to represent the dependence of the dependent parameter on the independent parameters. Here, the experimental data from various studies available in the literature are utilized for the development of the model. The experimental data are normalized on the basis of their maximum value considered among all the experiments in the study. The normalized data are further non-linearly regressed to a fourth-order polynomial using Microsoft Excel 2007 to obtain the model equation. The model equation is developed indicating the dependence of dependent parameter (adsorption capacity) on the independent parameters (initial metal concentration, pH, contact time and adsorbent dosage). The proposed generalized equation is validated using various experimental results from the literature and the parameters of the model equation are being estimated. The modeled equation is later being optimized by applying a specific optimization technique (differential evolution). A code of differential evolution is being developed using the platform of MATLAB 7 for the optimization of the models.
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    Removal of Cr(VI) from wastewater using activated neem bark in a fixed-bed column: interference of other ions and kinetic modelling studies
    (Taylor & Francis, 2015-04-07) Gupta, Suresh; Maheshwari, Utkarsh
    Continuous adsorption experiments are carried out in a fixed-bed to evaluate the performance of a newly developed low-cost adsorbent (activated neem bark, ANB) for the removal of Cr(VI) along with other metal ions (Cu & Zn) from aqueous solutions. The effect of initial Cr(VI) concentration, mass of adsorbent and flow rate on the breakthrough curve are studied. It is observed that as there is an increase in the initial concentration of Cr(VI) from 50 to 100 mg L−1, the mass of the adsorbent from 25 to 175 g, and flow rate from 5 to 15 mg L−1, the breakthrough time decreases from 24.78 to 13.875 h, increase from 9.25 to 111.66 h and decrease from 35.09 to 8.26 h, respectively. The effect on the performance of the ANB for Cr(VI) adsorption is also studied in the presence of Cu and Zn. The breakthrough time is achieved earlier in the presence of Cu and Zn in the feed stream. The fixed-bed adsorption process parameters such as saturation loading capacity, breakthrough time, total percentage removal of Cr(VI), the fraction of unused bed length, adsorption exhaustion rate and empty bed residence time are calculated for different experimental runs. The experimental results are likewise applied to the Yoon–Nelson and the Yan kinetic models. The kinetic parameters for both the models are calculated and reported in this study.
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    Efficient adsorbent for simultaneous removal of Cu(II), Zn(II) and Cr(VI): Kinetic, thermodynamics and mass transfer mechanism
    (Elsiever, 2015-11) Gupta, Suresh; Maheshwari, Utkarsh
    Present study deals with the development of a nano-porous adsorbent using neem bark for the simultaneous removal of Cu(II), Cr(VI) and Zn(II). The developed adsorbent is characterized using SEM, EDS and TGA. The effect of initial metal concentration, contact time, adsorbent dosage, temperature and pH are studied to see the performance of nANB for the metal ions removal. Various isotherm, kinetic and mass transfer models are validated with the experimental data and corresponding parameters are estimated. The maximum adsorption capacity of the developed adsorbent for Cu(II) and Zn(II) adsorption are found to be 21.23 and 11.904 mg g−1, respectively. The optimum parameter values for contact time, adsorbent dosage, temperature and pH are obtained as 48 h, 6 g L−1, 35 °C and 1.2, respectively, from the experimental results of Cu(II) and Zn(II) removal using nANB. The performance of nANB on the industrial effluent is evaluated by performing equilibrium batch experiments for the simultaneous removal of Cu(II), Cr(VI) and Zn(II) from an aqueous solution. The overall adsorption capacity of the nANB for the removal of multiple metal ions at 200 mg L−1 of each is obtained as 38.95 mg g−1 which is more than double for that obtained for individual metal ions.