SYSTEMATIC STUDY OF THE PH RANGES AND BUFFERING CAPACITY OF MIXTURES OF TRISODIUM ORTHOPHOSPHATE OR TETRASODIUM PYROPHOSPHATE WITH BORIC ACID

Assist. Prof. Mariya Georgieva, PhD

Institute of Mineralogy and Crystallography, Bulgarian Academy of Sciences

E-mail: marigeorgiewa@gmail.com

Assist. Prof. Stephan Kozhukharov, PhD

E-mail: s.kozhukharov@uctm.edu

Assoc. Prof. Christian Girginov, PhD

E-mail: girginov@uctm.edu

Assist. Prof. Pavlina Bancheva-Koleva, PhD

Department of Physics University of Chemical Technology and Metallurgy - Sofia

E-mail: bancheva@uctm.edu

Abstract

This study presents a systematic investigation of the pH ranges and buffering capacity of two systems composed of phosphate alkaline components and boric acid as the acidic counterpart. The alkaline components selected were trisodium orthophosphate dodecahydrate (Na₃PO₄.12H₂O) and tetrasodium pyrophosphate decahydrate (Na₄P₄O₇.10H₂O). The experimental work was carried out in two stages: (i) determination of pH ranges and (ii) evaluation of buffering capacity. All measurements were performed in quintuplicate using a high-precision pH meter. The results, including the complete set of raw data, are provided to serve as a useful reference for future studies. Detailed descriptions of the experimental procedures and calculation methods are also included, enabling reproducibility and further exploration. Although the investigated phosphate/borate mixtures displayed limited buffering capacity, they may nevertheless find application in chemical and electrochemical surface treatment processes.

Keywords

Na₃PO₄.12H₂O, Na₄P₂O₇.10H₂O, H₃BO₃, pH ranges, Buffering Capacity

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