Unfortunately, preventing or disabling the ability to put a mobile phone on silent without unlocking the screen lock is generally not possible on most standard Android or iOS devices. This functionality is intentionally designed for quick access and convenience.
You can't completely block access to volume controls from the lock screen, but you can limit the quick settings accessible on the lock screen by removing the "Sound" option from the quick settings panel, which will require unlocking the phone to adjust volume levels fully.
