Modification of activated carbon from processed salak fruit waste with Fe<sub>3</sub>O<sub>4</sub> composite for removal of Pb(II) in wastewater

Pb(II) is a heavy metal that is harmful to health and the environment.This metal is often found in industrial waste so it needs to be removed.One way to reduce these heavy metals is to use activated carbon.Various types of organic materials and agricultural waste can be made into activated carbon..One of the agricultural wastes that has great potential as activated carbon is salak seeds.This research processed salak seeds into activated carbon and modified them into Magnetic Activated Carbon (MAC).The research aims to obtain: 1) the best operating conditions for activated carbon production and MAC; 2) characteristics of activated carbon and MAC; 3) % removal of Pb(II) from liquid waste with MAC; 4) isotherm adsorption equation Pb(II) by MAC; 5) the kinetics equation of Pb(II) adsorption by MAC.The research method is to make activated carbon by carbonization, chemical and physical activation.The chemical activator used is a mixture of phosphoric acid -hydrochloric acid with a composition (1: 1).The next step is to make a MAC from activated carbon.Activated carbon characteristics were tested using the BET, SEM, EDX, and ASTM standard proximate tests.The results showed that activated carbon met SNI standards with iodine number 1230.93-1256.31mg/g, surface area 539.147 m2/g, pore volume 44.0262-112.5906cc/g.MAC contains 1% water, 21.88% volatile matter, 38% ash, 39.12% fixed carbon, and 1243.62 mg/g iodine number.Further findings show that the adsorption isotherm equation is best using the Freundlich equation.The Freundlich equation constants n = 1.3530 and K F = 34.634mg/g with R 2 = 0.913, while the Langmuir equations b = 0.7442 L/mg and qm = 78.125 mg/g with R 2 = 0.6692.The Pb(II) adsorption kinetics test by MAC showed pseudo-2nd order adsorption kinetics with the constant k 2 = 0.2737 g/mg.min and R 2 = 1.