Case Study: Aluminum removal from manufacturing wastewater

Challenge

GRAFTA Nanotech Inc is working with an engineering firm to resolve aluminum contamination in petrochemical cooling waters.

The subject water to be treated is the cooling water used in a petrochemical manufacturing facility. Through the cooling process the water becomes contaminated with a relatively high concentration of aluminum (i.e. 2.14 mg/L) which hinders the circulation of water back into the cooling process or environmental discharge.

Solution

GRAFTA™ 1.0 is an engineered graphene-based nanotechnology developed to target specific metals such as aluminum.

Removal of the aluminum is achieved through adsorption on graphene oxide nanosheets, with the graphene and graphene oxide layers of GRAFTA™ 1.0 providing the most efficient platform with an end result water quality that lowers the concentration of the target contaminant to levels approaching nondetectable concentrations.

Test Results

A raw water sample, with an aluminum concentration of 2.14mg/L, was used in a single column test, containing GRAFTA™1.0 (G1).

The column contained about 600g of G1 which was permeated under an upflow hydraulic regime, at a contact time of 10 minutes, for 40 pore volumes (amount of water received from the customer.

The results as shown in the following chart, indicated that GRAFTA™1.0 was capable of adsorbing aluminum from the subject water with 99.7% efficiency, lowering the concentration from 2.14mg/L to 0.0058mg/L.

Implementation and Design Considerations

A field application was designed for a flow rate of approximately 600 m3 per day using a lead-lag system to maximize the longevity. Longevity of GRAFTA™1.0 is estimated to be anywhere between 3 to 9 months depending on variations in loading.

Key steps in the process will include:

Water to be pretreated to remove plastics residuals from the manufacturing processes;
Waters received to be processed have a high concentration of aluminum;
Waters are split into 2 parallel streams;
Waters will be processed via lead/lag structure of 2- (10 m3) vessels in series taking approximately 75 gallons/minute of contaminated waters. The lag vessel will be idled until the levels of contaminant being released by the lead vessel reaches the limit for recycling the waters.
The cleaned waters will be recycled into the cooling system thus minimizing the amount of waters required to be purchased by the client for the process.