In this study a cost-effective adsorbent was prepared from phosphate rock waste. An abundant phosphate rock waste was generated, as by-product, from phosphate concentration processes. Phosphate rock waste was activated by chemical activators (including  different concentration of HNO3 and  NaOH or with both). The developed adsorbent was characterized using different techniques (XRD, XRF and SEM). Batch experiments were conducted to test the heavy metal ions (Cd+2, Cu+2, Ni+2, Pb+2 and Zn+2) removal efficiency by the developed adsorbent. The adsorption process was evaluated as a function of various operating parameters such as contact time, solution pH, temperature, initial metal ion concentration, and adsorbent dosage. The results concluded that activation phosphate rock waste was effective with 2M HNO3, and the developed adsorbent is suitable for effective removal of Cd+2, Cu+2, Ni+2, Pb+2 and Zn+2 from aqueous solution. Initial uptake of these metal ions increases with time and reaches equilibrium at 60 min, while the optimum adsorbent dosage and solution temperature were 0.5 g 100 mL-1 and 25°C, respectively. The adsorption process was pH-dependent with high adsorption capacity at pH 7. The experimental isotherms data were analyzed using the Langmuir, and Freundlich   models. The data obtained from adsorption isotherms of metal ions at different time fitted well to linear form of Langmuir model.

Nowadays finding the Easy and Economical way to treat the industrial wastewater is the raising ideas in newer technology. In this work adsorption of methylene blue using various adsorbent such as groundnut shell, and tea waste were used in batch studies at a constant dye concentration of 300 mg/l, adsorbent dose of 0.5 gm groundnut shell powder, and Spent tea powder. The time of Agitation was varied by 20, 40, 60, 80, 100 min. After the time of agitation of 100 min, Maximum dye removal of 86% was observed in spent tea powder and 80% was observed in Groundnut shell powder.

Adsorption is the adherence to a surface of atoms, ions, or molecules from a gas, liquid, or dissolved solid. This method produces an adsorbent film on the adsorbent's ground. In the present study, Ulva intestinalis (formerly Enteromorpha intestinalis) a member of Cyanophyceae collected form Covelong, Southeast coast of Tamil Nadu was used for adsorbing methyl orange and phenol red. The results showed that at 60 min of treating the phenol red dye with seaweed yield maximum reduction (44%) of colour and in case of methyl orange 47.4% colour reduction occurred after 60 min.