Abstract To avoid deficiencies of traditional electrocoagulation process, electrocoagulation process powered by renewable photovoltaic energy has been directly used to remove nickel from wastewater. Results show that under the solar irradiation intensity (SII) of 750 ± 30 W/m2, aluminum electrode has higher nickel removal efficiency (NRE) than graphite and titanium, and its NRE is nearly 100% in 40 min. An optimum distance of 20 mm is determined for the electrode gap. NRE in 40 min nearly decreases from 99.6% to 78.8% when initial Ni2+ co...