iPhone how to disable sound notifications at work
This can be done by scheduling Do Not Disturb.

Go into Settings → Do Not Disturb and enable Scheduled from 9 a.m. To 5 p.m.

Under Allow Calls From you may allow certain people to call you even while Do Not Disturb is active. Calls silenced by Do Not Disturb will go directly to voicemail.

At your discretion, you may also choose to Always silence notifications, or Only while iPhone is locked.

Emergency and Amber Alerts will still blare through Do Not Disturb. Those may only be silenced by toggling the hardware Mute switch, or by disabling them at the bottom of the Notifications menu.