Remove duplicates from 2D list Python

I'm using a 2D shape array to store pairs of longitudes+latitudes. At one point, I have to merge two of these 2D arrays, and then remove any duplicated entry. I've been searching for a function similar to numpy.unique, but I've had no luck. Any implementation I've been thinking on looks very "unoptimizied". For example, I'm trying with converting the array to a list of tuples, removing duplicates with set, and then converting to an array again:

coordskeys = np.array[list[set[[tuple[x] for x in coordskeys]]]]

Are there any existing solutions, so I do not reinvent the wheel?

To make it clear, I'm looking for:

>>> a = np.array[[[1, 1], [2, 3], [1, 1], [5, 4], [2, 3]]] >>> unique_rows[a] array[[[1, 1], [2, 3],[5, 4]]]

BTW, I wanted to use just a list of tuples for it, but the lists were so big that they consumed my 4Gb RAM + 4Gb swap [numpy arrays are more memory efficient].