I'm just learning how to use the Arduino Uno and I'm trying to control the speed of an AC fan. I made a sketch of this project on proteus but the triac seems not to be responding. I guess there's a problem with the attachInterrupt part of the code. Here's the code:

#define triacPulse 5
#define interruptPin 2

//button event
#define button1 6

void setup() {
  // put your setup code here, to run once:
  pinMode(button1, INPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  if(button1==HIGH){
    attachInterrupt(0, triacControl, FALLING);
  }
}

void triacControl()
{
  delay(5);   //delay for 5 milliseconds
  digitalWrite(triacPulse, HIGH);
  delay(5);
 
  digitalWrite(triacPulse, LOW);
}

Thanks for the answer in advance