OICC Press Journal of Nanostructure in Chemistry 2193-8865 9 4 (December 2019) 2019 10 23 Improvement of dyes removal from aqueous solution by Nanosized cobalt ferrite treated with humic acid during coprecipitation 10.1007/s40097-019-00318-9 EN Shaimaa M. Ibrahim Chemistry Department, Faculty of Education, Ain Shams University, Cairo, EG Abdelrahman A. Badawy Physical Chemistry Department, National Research Centre, Cairo, 12622, EG Hisham A. Essawy Department of Polymers and Pigments, National Research Centre, Cairo, 12622, EG Journal Article 2019 10 23 Abstract Highly effective novel adsorbent [CoFe 2 O 4 -humic acid(HA)] was synthesized by co-precipitation technique at pH 6 (H6) and pH 8 (H8). XRD, S BET and Zeta-potential measurements were used to study the physicochemical properties of the prepared nanoparticles. XRD results showed that the chemical treatment of CoFe 2 O 4 by HA causes the appearance of carbon as new active sites for adsorption process. Batch adsorption tests were achieved to eliminate anionic remazole-red (RR-133) and cationic methylene blue (MB) dyes. The obtained data showed that H6 and H8 solids calcined at 300 and 500 °C have higher adsorption rate for removing of dye than unmodified cobalt iron mixed oxide. The removal reached 100% after a period of dye contact time 2 min and 30 min for RR and MB, respectively. The uptake of RR and MB was much affected by the pH of dye solution. The pseudo-second-order kinetic model was the most fitted well and the adsorption process followed the Langmuir isotherm model. The adsorption of dye on adsorbent was chemisorption process. The as-prepared adsorbents can be regenerated and reused four times for both dyes. The efficiency of the prepared nano-samples and durability as adsorbent were accomplished. Graphic abstract