Paper ini membahas pembuatan dan karakterisasi arang aktif dari batang tanaman gumitir (Tagetes erecta) dengan aktivator H3PO4. Penelitian ini bertujuan untuk membuat dan menentukan karakteristik arang aktif dari limbah batang tanaman gumitir serta menentukan konsentrasi optimum H3PO4 yang dibutuhkan untuk mendapatkan arang aktif dengan karakteristik yang baik ditinjau dari kadar air, kadar zat mudah menguap, kadar abu total, kadar karbon, daya serap terhadap metilen biru, dan daya serap terhadap iod. Selain itu, dilakukan juga analisis spektra secara FTIR terhadap arang aktif dengan karakteristik yang terbaik. Secara umum, bila dibandingkan dengan standar mutu SNI 06-3730-1995 tentang arang aktif teknis maka aktivasi dengan berbagai konsentrasi H3PO4 dalam penelitian ini menghasilkan arang aktif dengan karakteristik yang baik, akan tetapi aktivasi dengan asam fosfat sebesar 15% menunjukkan karakteristik yang terbaik yaitu: kadar air 4,67 ± 0,33%, kadar zat mudah menguap 5,59 ± 0,33%, kadar abu 5,67 ± 0,33%, kadar karbon 84,33%, daya serap terhadap metilen biru sebesar 162,84 ± 0,50 mg/g dan daya serap terhadap I2 sebesar 759,62 ± 3,07 mg/g. Hasil identifikasi dengan spektrofotometer FTIR menunjukkan bahwa arang aktif tersebut mengandung gugus fungsi OH, C-H alifatik, P=O dan P-OH.

Dalam penelitian ini dilakukan pembuatan dan karakterisasi arang aktif dari batang tanaman gumitir (Tagetes erecta) menggunakan aktivator NaOH. Penelitian ini bertujuan untuk membuat arang aktif dan menentukan konsentrasi NaOH optimum yang dibutuhkan untuk mendapatkan arang aktif dengan karakteristik yang baik ditinjau dari kadar air, kadar zat mudah menguap, kadar abu total, kadar karbon, daya serap terhadap metilen biru, dan daya serap terhadap iod. Hasil penelitian menunjukkan bahwa arang aktif yang diaktivasi dengan natrium hidroksida (NaOH) 2,5% menghasilkan arang aktif dengan karakteristik terbaik dan memenuhi standar baku mutu SNI 06 – 3730 – 1995 tentang arang aktif teknis. Arang aktif yang diperoleh dalam penelitian ini memiliki kadar air sebesar 1,25 ± 0,02%, kadar zat mudah menguap sebesar 12,00 ± 0%, kadar abu total sebesar 5,33 ± 0,41%, kadar karbon sebesar 81,41%, daya serap terhadap metilen biru sebesar 199,97 ± 0,07 mg/g, dan daya serap terhadap I2  sebesar 728,09 ± 2,16 mg/g. Hasil analisis dengan spektrofotometer FTIR menunjukkan bahwa arang aktif tersebut mempunyai gugus fungsi C-H alifatik, C=O, C=C aromatik, dan O-H ikatan hidrogen

The stems of marigold plant can be used as the raw material for making activated carbon. One of the activators that can be used is NaOH with an activated time of 24 hours. The purpose of this study was to obtain an effective activation time through activation with a 2.5% NaOH activator in several variations of activation time followed by characterizing the activated carbon formed. Characterization which was carried out including the determination of water, volatile matter, ash, carbon contents, as well as the absorption capacity of methylene blue and iodine. The results of the study showed that the activation for 28 hours produced an activated carbon with characteristics in accordance with SNI 06-3730-1995, namely: water content (8.40 ± 0.72)%, volatile matter content (9.58 ± 0.95) %, ash content (4.93 ± 0.83)%, carbon content of 77.09%, absorption of iodine (758.66874 ± 1.21) mg/g and absorption of methylene blue 124.6226 mg/g. The results of the analysis with FTIR spectrophotometer on this activated charcoal showed the presence of OH, CH aliphatic, C = O and C = C functional groups.   Keywords: activated carbon, sodium hydroxide, marigold plant stems

This paper discusses the manufacture and characterization of activated carbon from bamboo apus (Gigantochloa apus) with H3PO4 activator. The aims of study were to determine the optimum carbonization temperture and  time as well as the amount of phosphoric acid required as the chemical activator. In addition, the activated carbon was also characterized following the Indonesian National Standard (SNI-1995) for activated carbon. Tthe activated carbon functional groups was determined using FTIR spectroscopy. The result showed that the optimum temperature of carbonization was 600oC, the carbonization time was 90 minutes and the  phosphoric acid  required was 20 gram for 1 gram carbon. Under these conditions, the activated carbon resulted met SNI-1995 with the characteristics as follows:  the water content was (1.11±0.83%), the level of volatile substances was (8.13± 0.27%), the total ash amount was (7.33±1.35%), the carbon contents was (83.40±0.27%). and the absorption capacities of iodine and methylen blue were of 1057.75 mg/g, 472.88 mg/g, respectively. FTIR identification indicated the existence of some functional groups, namely aromatik, ketone, and hydroxyl.

A method is described for the reliable determination of copper, lead, cadmium and zinc in natural waters by anodic stripping potentiometry mth the use of a novel combined electrode. The method involves two stripping cycles during whch copper is initially determined on its own, followed by simultaneous determination of lead, cadmium and zinc after addition of gallium (111) ions. The optimum conditions include 0.01 M HCI as supporting electrolyte, 10 mgL Hg (11) as chemical oxidant; Edep(cu) -700 mV vs Ag/AgCI; Edep(pb,cd,&) -1200 mV VS AglAgC1; tdep 10s; 150 pg/L Ga (111); sample rotation rate 5 and rest period 30s. Under these conditions, as low as 0.06 pgL Cu ( 0.7% RSD ); 0.2 p g L Pb ( 13% RSD ); 0.04 pg/L Cd ( 7.8% RSD ) and 0.06 pg/L Zn ( 5.5% RSD ) can be determined reliably. A linear concentration range of 0 -110 pg/L was obtained for the four metals.The successful application of the method to reference fresh water, creek water and tap water is demonstrated.