You need to show me a schematic. Post here a link. And, “a little bit” does not say much. By how much is it shifted?

On the hardware implementation (TL082), the phase of the output waveform is shifted a little bit and I dont know why..Would you help me

You need to change the reference. negative resistor values means that, physically, the circuit needs another power supply in series with that resistor value. To avoid that, you need to play with the reference if you use a calculator, or use the equations to calculate the reference.

It should work. The circuit shown is for any op amp. You choose an op amp based on your application: precision, bandwidth, power supply, noise level, etc.

I have a bipolar to unipolar calculator here: Bipolar to Unipolar Converter Example. Plug your numbers, and you will see that the answer is R1 = R3 = 10 kohm, R2 = R4 = 2.94 kohm, with a Vref = 2.5V.

An op amp has to have its outputs and inputs at voltage levels which are between V- and V+. In this case, the output is always positive and the op amp inputs are positive as well. So, you can use only a positive supply with one condition: The op amp has to have a rail to rail output. And that’s because the output has to go down to 0 volts. If the negative power supply is at 0V, the output cannot reach zero, if the op amp is not rail to rail. That is why, considering that this is a general purpose op amp with the output span of about (V+) – 1V to (V-) + 1V, I chose to have a negative supply as well.