Can money earned from a job that involves negligence and a lack of sufficient care—due to distress and a desire to leave it—be purified by giving charity from it?

What you do by way of negligence and dereliction in work is impermissible, and you must repent and return the equivalent of the hours of dereliction to the employer, unless they absolve you of it. Giving it away as charity is not sufficient if returning it is possible. Cease your negligence and perform the work entrusted to you to the fullest extent; in fulfillment of the contract and as an discharge of the trust; for Allah Almighty says: "O you who have believed, fulfill [all] contracts."