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Background: Nowadays, water pollution by toxic elements has become a universal environmental issue. Lead, as a toxic element, is approximately enhanced in the environment by industrial development. The potential risk of lead to health has attracted the interest of researchers to eliminate it from contaminated water. Objectives: In the present study, a dithizone-modified bagasse adsorbent, used for removing lead ions from aqueous solutions, was successfully prepared. Methods: The prepared adsorbent was characterized by FT-IR and XRD techniques. The adsorptive properties of adsorbent were studied at room temperature. Different parameters like pH value, solution concentration, adsorption time, and amount of adsorbent were optimized. Results: Results show that the adsorption of lead on dithizone-modified bagasse fitted well to the Freundlich isotherm equation following the Langmuir isotherm. The maximum removal efficiency was obtained to be more than 99.5% in a short contact time (1.0 minutes) at pH 6. The loading capacity was studied and obtained to be 37.20 mg g -1 . The adsorption process was replicated for 4 times without a considerable loss in its efficiency (> 95%). Conclusions: High efficiency at a short time, recyclability, and biodegradability are the main advantages of this adsorbent. The proposed method is cost-effective and environmentally friendly.

Background:Temephos is an organophosphate pesticide used as larvicide in the environment. Although not extremely hazardous, it can be risky for human health in the moderate concentrations. Objectives: This study investigated the quantitative removal efficiency of temephos, an organophosphate pesticide, from contaminated water by silver-modified ZVINPs. In addition, the operational parameters affected on removal process were optimized. Materials and Methods: In the current study, three water samples from different parts of Iran such as Ahvaz tap water, the Karoon River passing through Khoramshahr city, and the Caspian Sea were collected. A new method for effective removal of temephos from the sample solutions by silver modified zero-valent iron nanoparticles as an efficient adsorbent was introduced. Results: For a typical solution in which temephos was removed about 21% by iron zero-valent nanoparticles, modification by silver improved removal method was up to about 99%. The required time for the complete removal of temephos was about eight minutes. Variation of pH and concentration of KNO 3 as an electrolyte was considerably ineffective on the efficient temephos removal. Adsorption studies of the method were followed by Langmuir isotherm. Maximum temephos adsorption amount was 12.65 mg/g under optimal conditions. The proposed method was simple, fast and safe to treat temephos polluted waters. Preparation of the adsorbent was easy and removal time was short. Conclusions: Briefly, the current study represents a novel method to eliminate temephos as an organophosphate compound from water samples with modified zero-valent iron nanoparticles.