Scale prevention
is a long-term challenge. It is essential for
ensuring the optimum utilization of oil and gas wells and minimizing
economic losses due to disruptions in the hydrocarbon flow. Among
the commonly precipitated scales is calcite, especially in oilfield
production facilities. Previous studies on scale inhibitors have focused
on investigating the performance of several phosphonates and carboxylates.
However, the increased environmental awareness has pushed toward investigating
environmental-friendly inhibitors. Research studies demonstrated the
potential of using amino acids as standalone inhibitors or as inhibitor-modifying
reagents. In this study, 10 amino acids for calcite inhibitors have
been investigated using molecular simulations. Eco-toxicity, quantum
chemical calculations, binding energy, geometrical, and charge analyses
were all evaluated to gain a holistic view of the behavior and interaction
of these inhibitors with the calcite {1 0 4} surface. According to
the DFT simulation, alanine, aspartic acid, phenylalanine, and tyrosine
amino acids have the best inhibitor features. The results revealed
that the binding energies were −2.16, −1.75, −2.24,
and −2.66 eV for alanine, aspartic acid, phenylalanine, and
tyrosine, respectively. Therefore, this study predicted an inhibition
efficiency of the order tyrosine > phenylalanine > alanine >
aspartic
acid. The predicted inhibition efficiency order reveals agreement
with the reported experimental results. Finally, the geometrical and
charge analyses illustrated that the adsorption onto calcite is physisorption
in the acquired adsorption energy range.