**Efficient Removal of Lead, Copper and Cadmium Ions from Water by a Porous Calcium Alginate/Graphene Oxide Composite Aerogel**

#### **Linhai Pan 1, Zhuqing Wang 1,2,\*, Qi Yang 1 and Rongyi Huang 1**


Received: 1 November 2018; Accepted: 17 November 2018; Published: 20 November 2018

**Abstract:** In this study, we fabricated a porous calcium alginate/graphene oxide composite aerogel by using polystyrene colloidal particles as sacrificial template and graphene oxide as a reinforcing filler. Owing to the excellent metal chelation ability of calcium alginate and controlled nanosized pore structure, the as-prepared calcium alginate/graphene oxide composite aerogel (mp-CA/GO) can reach the adsorption equilibrium in 40 min, and the maximum adsorption capacity for Pb2+, Cu2+ and Cd2+ is 368.2, 98.1 and 183.6 mg/g, respectively. This is higher than most of the reported heavy metal ion sorbents. Moreover, the mp-CA/GO can be regenerated through simple acid-washing and be used repeatedly with little loss in performance. The adsorption mechanism analysis indicates that the mp-CA/GO adsorb the heavy metal ions mainly through the ion exchange and chemical coordination effects.

**Keywords:** Adsorbent; heavy metal ions; calcium alginate; graphene oxide; polystyrene colloidal particles template
