<div class="demo-container">
<ul>
  <li>First Item</li>
  <li>Second Item</li>
  <li>Third Item</li>
  <li>Fourth Item</li>
</ul> 
</div>

.demo-container li {
  position: relative; 
  list-style: none;
  padding-left: 30px;
} 
.demo-container li::before {
  position: absolute;
  font-family: 'FontAwesome';
  content: "\f138";
  left: 0;
}