:In the present study, methylene blue (MB) dye was removed by Azadirachta indica which was prepared using raw Neem leaves through successive unit operation in a batch process. The effect of various operating parameters like inlet concentration of MB dye, adsorbent dose, pH of solution, and contact time were studied on percentage removal of MB dye. It was observed that the percentage removal increased on increasing the adsorbent dose, pH and contact time. However, it decreases on increasing the dye concentration. The maximum removal was found to be 93.11 % at 1 gmof NLP dose under 180 minute of contact time for 10 mg/l MB dye solution. Moreover, various isotherm models viz Langmuir, Freundlich and Temkin were fitted through regression on batch experimental data and it was found that Freundlich isotherm model best fits since the value of R 2 (0.996) is maximum as compare R 2 value of other models. Further, the unsteady state kinetic models were fitted on experimental data for understanding the phenomena of type of adsorption and it was observed that Pseudo second order model was in close agreement with experimental data .The theoretical equilibrium adsorption capacity was also found to be well validated with experimental equilibrium adsorption capacity. The maximum adsorption capacity of NLP adsorbent was found to be 5.7 mg adsorbate adsorb/gm of adsorbent. The SEM images of new brand prepared adsorbent and used adsorbent after 180 minute of contact time shows that the NLP is an effective adsorbent for MB dye removal.

In this study, synthesised Azadirachta indica adsorbent was used for the removal of methylene blue dye using a packed bed column. The effect of feed flow rate, feed methylene blue dye concentration, and bed height of column on percentage removal of dye was studied. It was observed that the column bed exhausted rapidly at a higher flow rate and therefore, a breakthrough occurred faster. However, it was observed that bed exhaustion time increases on increasing the bed height from 2 to 10 inch at 10 mg/L feed dye concentration and feed flow rate of 40 ml/min. It was also found that the breakthrough curve is more dispersed and the percentage removal of dye increases on decreasing the feed methylene dye concentration from 150 to 10 mg/L. The percentage removal was found to be 96.89% at 20 ml/min of feed flow rate under 10 inch of bed height and 10 mg/L of feed dye concentration. The atomic absorption spectrophotometer and scanning electron microscope were used for estimating the effluent dye concentration from the column and morphological study, respectively.