Reduce noise in this op-amp buffer circuit
Is there any reason why you are using an op-amp in the first place? 

Now in case this is because you must use the op-amp please note that: by placing a resistor in the op-amp's input you are reducing its input impedance. This setup is inducing the ripple you see in the scope. If by placing the input resistor it's your intention to reducing the current, you are doing quite the opposite because the opamp already has a high input impedance. Taking off the resistor will reduce the load on the microcontroller's output thus reducing the ripple.







simulate this circuit &ndash; Schematic created using CircuitLab

Now, as the circuit is driving a LED, I would recommend a single rail op-amp like LM158. This will simplify your design as you won't have to worry about the reverse current on the LED.

If an op-amp is not a must, an open collector digital driver like the old 7407 would be enough.







simulate this circuit

Even if noise is an issue, you could use an Schmitt trigger buffer like 7417. 
These circuits work well up to 15 volts but there are devices available with higher rated voltages.
Now, if you want to simplify even more. Use a transistor as others have suggested.