Experimental data can be presented, computed, and critically analysed in a different way using statistics. A variety of statistical tests are used to make decisions about the significance and validity of the experimental data. In the present study, adsorption was carried out to remove zinc ions from contaminated aqueous solution using mango leaf powder. The experimental data was analysed statistically by hypothesis testing applying t test, paired t test and Chi-square test to (a) test the optimum value of the process pH, (b) verify the success of experiment and (c) study the effect of adsorbent dose in zinc ion removal from aqueous solutions. Comparison of calculated and tabulated values of t and v 2 showed the results in favour of the data collected from the experiment and this has been shown on probability charts. K value for Langmuir isotherm was 0.8582 and m value for Freundlich adsorption isotherm obtained was 0.725, both are \1, indicating favourable isotherms. Karl Pearson's correlation coefficient values for Langmuir and Freundlich adsorption isotherms were obtained as 0.99 and 0.95 respectively, which show higher degree of correlation between the variables. This validates the data obtained for adsorption of zinc ions from the contaminated aqueous solution with the help of mango leaf powder.

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Hypothesis testing is useful statistical tool understood as a critical testing of the experimental data. The experiment for the removal of heavy metal ions from aqueous solution by adsorption was carried out with the deliberate object of testing hypothesis through different tests meant for the purpose using available data obtained from experiments. Decisions about the validity and significance of the data were made on the basis of hypothesis testing. It enabled us to make probability statements about the adsorption parameters. In the present study, dried mango leaf powder was used to remove Cu, Zn and Pb from heavy metal samples prepared in lab. the experimental data was tested using different statistical tools namely Student’s t-tests, F-test to test the equality of variance of two normal populations, Chi-square test to test the effectiveness of the adsorption in removing heavy metal ions, ANOVA for the analysis of significance of difference between means of multiple samples at the same time, all within 5% level of significance.

Since ancient times, it’s a common practice in India to use mango tree leaves when there is a large crowd of people to ensure free flow of oxygen, for their ability to absorb excess carbon dioxide. Owing to its purifying nature, it has been studied for waste water treatment also. In the present study, potential of mango tree leaves have been investigated in removing zinc ions from aqueous solution. Batch adsorption studies were conducted to determine the optimum values of solution pH, zinc ion concentration in the solution, adsorbent dose and contact time at 20oC for maximum removal zinc ions from the synthetic solutions. It was observed that Zinc ion removal increased with increase in adsorbent dose and time. Optimum pH was 4. Equilibrium data was well described by the Langmuir, Freundlichand Temkin adsorption isotherm models.

Bio sorbents are commonly used inremoving toxic heavy metal ions from wastewater. Bel leaves are used in temples and immersed in water after offering prayers since ancient times. In the present study, a packed bed continuous column was used to remove lead ions from contaminated water with modified bel leaf powder. The bel leaf powder was polymerised during in-situ polymerisation of aniline in the presence of strong oxidant at low temperature. This modified polyaniline coated bel leaf powder had more capacity to adsorb lead ions. It adsorbed 97.6% lead ion as compared to 90% adsorbed by raw bel leaf powder. Packed column dynamics were also studied for different flow rates (5-25 mL/min) of the adsorbate at different depths along the column. Clogging of the pores and channelization was observed along the column with passage of time, which led to change in lead ion concentration, % removal, adsorption capacity and time of exhaustion along the length of the column. Maximum lead ion removal obtained was 19.1mg, 18.7 mg, 18.36 mg and 18.05 mg at the ends of sections S1, S2, S3 and S4. The exhaustion time was 46 mins, 51 mins, 61 mins and 70 mins respectively for sections S1, S2, S3 and S4. Desorption study showed 96.3% desorption of lead with 0.1 M HCl as eluent.