Executive Summary Jar tests were performed to consider the most effective conditions for maximum precipitation from synthetic wastewater. The samples were used to simulate industrial wastewater containing copper. Increasing dosages of NaOH were added to the samples in order to raise the pH level and cause precipitate formation. Copper concentration levels of 30, 3.45, 1.32, 0.98, 0.45, and 0.22 mg/L were observed when given 0, 5, 10, 20, 30, and 40 mL 1 M NaOH dosages, respectively. It was observed that, as the pH of the solution increased, the amount of precipitate formed also increased. In addition, as greater amounts of NaOH were added to the wastewater samples, the concentration of copper ions in the solution decreased. Introduction Chemical …show more content…
The 1 M NaOH was added to the beakers in doses of 0, 5, 10, 20, 30, and 40 mL, with one dosage in each beaker. The beakers were placed in the 6 staged mixer then stirred at 80 rpm for 2 minutes. The beakers were stirred at 40 rpm for 15 minutes to promote agglomeration. During this time observations on the precipitants were recorded. The mixer was deactivated and the solutions allowed to sit for 30 minutes to allow for settling. During this time observations on the precipitants were recorded. A sample of each beaker was pipetted from the top of the beaker without disturbing the precipitant and collected in sample bottles. The pH of the beaker solutions was measured using a laboratory table top pH meter. The samples of each beaker were tested later by lab TA and the concentration of Cu in each sample were measured as well as the concentration of Cu in the …show more content…
So, from the control as pH was increased, the concentration decreased. The lowest concentration value was seen at highest pH. These results are recorded in (Table 1) in the appendix. In (Figure 1) the samples are shown while they were allowed to settle. The clear jar is the control where no copper had precipitated and remains suspended. From the left to right, the sample became more cloudy with smaller clumps of precipitants. Even though the sample with 5 mL of NaOH added appeared to be the clearest of the non-control samples, it was clear because less copper had precipitated out of suspension. Discussion and Conclusion From the experiment, it was seen that an increase in pH caused a greater Cu2+ precipitation. The precipitation process creates solids from compounds that were once dissolved in solution, and these solids must be removed by filtration or sedimentation (Casiday et al 2008). However, this was the only variable that was tested. In order to increase the efficiency of the waste removal, mixing speeds and times, as well as resting times may be varied to reduce process time and efficiency. Also, depending on the setup of equipment and unique scenario, other chemicals may be preferable for inducing precipitation (EPA 2000). The ability to remove heavy metals, such as the Cu2+ ions in this experiment, is very important for water treatment applications. If left untreated, these