The error is that you are giving `LST_map` as an input to `Export.image.toDrive`, but `LST_map` is `ee.ImageCollection`. You can only export one image per Export task. 

Image export tasks are created with a call to a client-side function **Export.Image.toX** where X is toDrive, toAsset, or toCloudStorage (e.g. [Export.Image.toDrive](https://developers.google.com/earth-engine/apidocs/export-image-todrive)). 

You can make your [image collection into a list](https://developers.google.com/earth-engine/apidocs/ee-imagecollection-tolist) and then use [ee.List.get](https://developers.google.com/earth-engine/apidocs/ee-list-get):

```js
var n = myCollection.size().getInfo()  
var imgList = myCollection.tolist(n)
var img = imgList.get(0) 
```

You can wrap the `imgList.get(X)` and subsequent call to `Export.image.toDrive` in a loop or in a function, and create all the export tasks that you need. Note that this process requires the use of `.getInfo()` because Export.image.toX is a client-side function.

There are some third-party modules you can use to handle this process for you, both for javascript and python, some of which are listed below:

- https://github.com/fitoprincipe/geetools-code-editor/wiki/Batch
- https://github.com/gee-community/gee_tools
- https://github.com/gee-community/geemap/blob/master/geemap/common.py#L581