Reduction of Fluoride in Central Kyzylkum Phosphate Waste in an Acidic Environment: Experimental and Mathematical Study Based  on the Langmuir Model

Z. Kurayazov; A. Ollaberganova; M. Jabbarov; U. Matnazarov; R. Babajanova

doi:10.31643/2027/6445.41

Authors

Z. Kurayazov Urgench State University named after Abu Rayhon Biruni
A. Ollaberganova Urgench State University named after Abu Rayhon Biruni
M. Jabbarov Mamun university
U. Matnazarov Urgench State Pedagogical Institute
R. Babajanova Urgench State University named after Abu Rayhon Biruni

DOI:

https://doi.org/10.31643/2027/6445.41

Keywords:

Phosphate waste, Central Kyzylkum, fluoride, acidic environment, acidic wastewater, Langmuir model, fluorapatite, mathematical modeling.

Abstract

Below is a scientific article explaining the results of a comprehensive study on the desorption of fluoride from mineralized waste (MM) of the Central Kyzylkum phosphate deposits in an acidic environment, studied by experiments and mathematical modeling. The interaction between fluorapatite present in MM and acidic wastewater (AWW) was studied in detail. Acidic components in AWW, mainly free fatty acids, promote the decomposition of fluoride in MM through ion exchange mechanisms. Experiments were performed at 333 K with 30 minutes of mixing for different AWW: MM mass ratios from 100:10 to 100:40. The initial pH of the MM samples was close to neutral, while the pH of the AWW was 2.2; therefore, the pH in the mixtures was acidic. Values of qₑ (fluoride adsorbed per unit mass) and Cₑ (equilibrium fluoride concentration) were calculated for each mixture. Using these data, a regression graph was plotted according to the Langmuir adsorption model. A linear equation obtained from the graph gave q_max = 7.48 mg/g and K_L= 0.027 L/mg. An R² value of 0.93484 obtained from the Langmuir equation showed that the model and experimental results are in good correlation. Fluoride ions in AWW can be converted into HF gas by strong acids and released into the atmosphere. The identification of reaction products allowed them to propose a mechanism of decomposition. Two different streams of industrial wastes, MM and AWW, were combined in the current work, and this combination allowed the development of new technological solutions.

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Author Biographies

Z. Kurayazov, Urgench State University named after Abu Rayhon Biruni

Doctor of Philosophy in Technical Sciences, Associate Professor at the Faculty of Chemical Technology, Urgench State University named after Abu Rayhon Beruni, 220100, H. Olimjon Street 14, Urgench, Uzbekistan. ORCID ID: https://orcid.org/0000-0002-9217-0669

A. Ollaberganova, Urgench State University named after Abu Rayhon Biruni

Doctor of Philosophy in Technical Sciences, Associate Professor at the Faculty of Chemical Technology, Urgench State University named after Abu Rayhon Beruni, 220100, H. Olimjon Street 14, Urgench, Uzbekistan.

M. Jabbarov, Mamun university

Non-government Educational Institution Mamun University, Khiva, Uzbekistan. ORCID ID: https://orcid.org/0009-0001-5987-0057

U. Matnazarov, Urgench State Pedagogical Institute

Candidate of Pedagogical Sciences in the Faculty of Natural and Applied Sciences, Urgench State Pedagogical Institute, 220100, Gurlan str, 1-A, Urgench city, Uzbekistan.

R. Babajanova, Urgench State University named after Abu Rayhon Biruni

Doctor of Philosophy in Technical Sciences, Associate Professor at the Faculty of Chemical Technology, Urgench State University named after Abu Rayhon Beruni, 220100, H. Olimjon Street 14, Urgench, Uzbekistan.

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