Sigmoid Neutralization Response of Acidic Soapstock Waste by Mineralized Phosphorite Residues: A 4-Parameter Logistic Approach

S.X. Shamuratov; U.S. Baltayev; U.K. Alimov; M.E. Jabbarov; A.E. Madaminov

doi:10.31643/2027/6445.32

Authors

S.X. Shamuratov Urgench State University named after Abu Rayhon Biruni
U.S. Baltayev Urgench State University named after Abu Rayhon Biruni
U.K. Alimov Institute of General and Inorganic Chemistry, Academy of Sciences of the Republic of Uzbekistan
M.E. Jabbarov Mamun University
A.E. Madaminov Urgench State Pedagogical Institute

DOI:

https://doi.org/10.31643/2027/6445.32

Keywords:

neutralization, dose–response, 4-parameter logistic (4PL), pH–CaO correlation, operational optimization.

Abstract

This study investigates the neutralization behavior of an acidic wastewater (AWW)–mineralized mass (MM) system at mass ratios ranging from 100:10 to 100:40, processed at 333 K for 30 min. The evolution of pH as a function of MM dosage and the corresponding CaO content (%) in the solid phase were quantitatively evaluated. The solution pH increased sigmoidally from 4.10 to 7.30, while the CaO content rose from 23.92% to 36.96%, approaching a saturation plateau at higher MM dosages. The pH–dose relationship was described using four-parameter logistic (4PL), Gompertz, and Weibull models, all showing a high goodness of fit (R² ≥ 0.97). Model comparison based on AICc and BIC criteria indicated that the Gompertz model provided the best statistical performance, whereas the 4PL model ensured clearer physicochemical interpretability. A strong positive correlation between pH and CaO content was established (Pearson r = 0.9649, n = 7, p < 0.001), enabling estimation of CaO content from pH values. Numerical inversion of the 4PL model combined with a multi-model ensemble approach was used to determine optimal MM dosages for target pH levels. The recommended operating conditions were identified as 100:32 for pH 6.5, 100:36 for pH 6.8, and 100:38 for pH 7.0, with a stabilization zone observed at 100:37–100:40.

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Author Biographies

S.X. Shamuratov, 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 Biruni, Urgench, H. Olimjon Street 14, 220100, Uzbekistan. ORCID ID: https://orcid.org/0000-0002-1040-1807

U.S. Baltayev, Urgench State University named after Abu Rayhon Biruni

Candidate of Technical Sciences, doctoral student in the Faculty of Chemical Technologies, Urgench State University named after Abu Rayhon Biruni, Urgench, H. Olimjon Street 14, 220100, Uzbekistan. ORCID ID: https://orcid.org/0009-0004-5636-3318

U.K. Alimov, Institute of General and Inorganic Chemistry, Academy of Sciences of the Republic of Uzbekistan

Doctor of Technical Sciences, leading scientific researcher at the Institute of General and Inorganic Chemistry, Academy of Sciences of the Republic of Uzbekistan, 77, Mirzo Ulugbek, Tashkent 100170, Uzbekistan. ORCID ID: https://orcid.org/0000-0001-5608-5304

M.E. Jabbarov, Mamun University

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

A.E. Madaminov, Urgench State Pedagogical Institute

Doctor of Philosophy in Pedagogical Sciences, Associate Professor in the Faculty of Natural and Applied Sciences, Urgench State Pedagogical Institute 1-A, Gurlan str, Urgench city, 220100, Uzbekistan. ORCID ID: https://orcid.org/0000-0002-3482-8071

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