Buttler was fined 15 percent of his match fee and given one demerit point by the International Cricket Council for an expletive-laden outburst against South Africa's Vernon Philander.
The incident was captured on the stump microphone and widely distributed on social media.
"I fully understand that as role models we have a duty to behave in a certain way," said Buttler as England started their preparations for the third Test starting at St George's Park on Thursday.
"I'd like to apologise. I understand that's not the way to behave so I'll take the slap on the wrist and move on."
He ascribed his behaviour to "heat of the moment and a bit of redness".
Asked his opinion on stump microphones staying switched on during play, Buttler said he believed there were arguments both for and against.
"In Test cricket there's a lot of high emotions at times and things being said that don't necessarily mean anything but for viewers at home come across very poorly," he said.
"We understand that it adds to the viewership experience, having stump mics and being able to hear a bit what goes on," said Buttler.
England were criticised for being "too quiet" during a Test series defeat in New Zealand towards the end of last year but Buttler said there had been no conscious effort to lift the team's aggression in South Africa in a series which is locked at 1-1 with two matches to play.
"Not at all," said Buttler. "I think actions speak as loud as words."
He said the energy created by young players in the team contributed to putting pressure on South Africa during England's 189-run win in Cape Town.
"There's more than way of doing it and it doesn't have to be vocal."
Buttler said that although the first two Tests had been fiercely contested, they had been conducted in a good spirit.
He felt England would take some momentum into the third Test after their performance in Cape Town, which was dominated by a century by Dom Sibley and the all-round efforts of man of the match Ben Stokes.
"Everyone just rides off the back of Ben Stokes," said Buttler. "He's pretty super-human at the moment and he generates a lot of confidence for everyone."
Buttler said England would miss the injured James Anderson, "the best seam bowler we've ever had" but fast bowlers Jofra Archer and Mark Wood had both recovered from injury and were bowling at high pace.