2188 Introduction Colour removal from wastewater/effluents is of great im- portance. Various industries such as textile, paper, carpet, leather, distillery, and printing are responsible for the dis- charge of wastewater containing dyes into rivers and natural water streams, these dyes prove to be toxic to the aquatic life and damage the ecosystem 1,2 . This toxic wastewater that is polluted due to chemicals worsens the water and soil quality after mixing with rivers, natural streams, and its dependent habitat and environment 3 . As a consequence of such high quantities of effluent and dye-bearing wastewater, these in- dustries are now facing major problems in environmental J. Indian Chem. Soc., Vol. 97, No. 11a, November 2020, pp. 2188-2194 Adsorption of Rhodamine-B by using Citrus peel powder: Influence of operating parameters Niraj S. Topare* a,b , Sudarshan Surange a , Aishwarya Chaudhari a , Sunita Raut-Jadhav c , Satish V. Khedkar d and Shantini A. Bokil e a Department of Petrochemical Engineering, MAEER’s, Maharashtra Institute of Technology, Pune-411 038, Maharashtra, India * b School of Chemical Engineering, Dr. Vishwanath Karad MIT World Peace University, Pune-411 038, Maharashtra, India c Department of Chemical Engineering, Bharati Vidyapeeth (Deemed to be University) College of Engineering, Pune-411 043, Maharashtra, India d Department of Chemical Engineering, College of Engineering & Technology, Akola-444 104, Maharashtra, India e Department of Chemical Engineering, Dr. Vishwanath Karad MIT World Peace University, Pune-411 038, Maharashtra, India E- mail: niraj.topare@mitwpu.edu.in, nirajtopare06@gmail.com Manuscript received online 20 October 2020, revised and accepted 31 October 2020 Rhodamine-B (RB) is widely used for different purposes in industries such as printing and dyeing in paints, paper, leathers, textiles, etc. and may remain in high concentrations in surface water used as drinking water sources. In this study removal of RB from aqueous solution using Citrus peel powder (CPP) has been investigated. The influence of various factors such as the amount of a concentration of RB (20, 40, 60, 80 mg/L), adsorbent (CPP) dosage (0.5, 1.0, 1.5, 2.0, 2.5 g/L), pH (3, 5, 7, 9, 11), agitation speed (100, 200, 300 rpm) and temperature (40, 50, 60ºC) were studied. It has been found that maximum adsorption is occurring at 2 g/L amount of adsorbent, dye the concentration of 20 mg/L, pH of 3, agitation speed 300 rpm at 60ºC. Equilibrium data were fitted to Langmuir and Freundlich isotherms and the equilibrium data were best described by the Langmuir isotherm model with 125 mg/g at 60ºC. The values of their corresponding constants were determined from the slope and intercepts of their respective plots. The results of this study indicate that the adsorption is favorable and suggested that natural adsorbents can be utilized as adsorbent materials, because of their selectivity for the removal of RB from aqueous solutions. Keywords: Rhodamine-B, Citrus peel powder, adsorption isotherms, process parameters. pollution 4 . In many of the cases, effluent wastewater from such in- dustries is directed towards the natural stream of water and thus poses a severe hazard to the environment and local flora and fauna 4 . Wastewater effluents discharged from in- dustries and containing even small amounts of dyes is of high priority matter of concern as it causes a change in prop- erties and color of water and has a long term damaging ef- fect on aquatic life 5 . Due to the fact that this dye bearing wastewater imposes severe health harm to humans, there is a strong need for developing an eco-friendly, robust, and cost- effective method to treat the dye contaminated wastewater 6 .